user13709: Searching the Pali Canon for the "root of suffering", we find the direct  definition only occurs in a few suttas:

delight is the root of suffering (MN1)
attachment is the root of suffering (MN105, MN66)
desire is the root of suffering ([MN42.11])
what is greed? ... that which is...root of suffering (Vb17)

We also have that ignorance is simply one product of dependent origination (SN 22.81):

And that craving, that feeling, that contact, and that ignorance are also impermanent, conditioned, and dependently originated.

Ignorance does indeed result in suffering, but to claim it as the root of suffering feels a bit misleading. 
Can one assert “ignorance is the root of suffering?” 
Can one assert “ignorance is NOT the root of suffering?”
In your answers, kindly include actual sutta references, preferably from the Pali Canon. This is necessary to avoid arguing about personal interpretation since supported translations are provided by ordained and well-respected monks. As a Sangha, we have to respect and uphold the Dhamma. 


user11541: It is true that craving, feeling, contact, and ignorance are impermanent, conditioned, and dependently originated.
Coming together of Ignorance and Contact gives rise to Craving which in turn gives rise to Suffering. If we abandon Ignorance or Contact or Craving or Feeling completely, the Suffering will cease. Therefore in a sense all of the above factors of dependent origination can be called the root of suffering. 

user8157: The question requires understanding exactly what the word "mūla" ("root") is meant to mean in terms of its general usage (which I cannot answer at this current time and requires a contextual analysis of the texts). However, given "attachment" actually is suffering itself, the word "root" may not mean a "preceding cause" ("hetu") but be something much closer to the subject/thing. 

Delight in feelings is attachment - MN 38
In short, suffering is the five aggregates attached to - SN 56.11
Conceiving 'self' is an arrow, disease, cancer - MN 140
Resolved on 'my self'... is suffering arising... SN 12.15
View of 'a being'... is suffering arising... SN 5.10

In SN 42.11, 'root' is used as a preceding cause; although 'chando' is not as exact as 'tanha': 

For desire is the root of suffering. Chando hi mūlaṃ dukkhassa.

In MN 22, something that is essentially 'causeless', namely, ignorance, is cut off at its root: 

Herein the monk has abandoned ignorance, has cut it off at the root..
Abandoned the round of re-births, leading to renewed existence; he has cut it off at the root...
Abandoned craving, has cut it off at the root...
Abandoned the five lower fetters, has cut them off at the root...
Abandoned the conceit of self, has cut it off at the root...

The contextual analysis becomes more clear with SN 15.9, which says:

Suppose a stick was tossed up in the air. Sometimes it’d fall on its bottom, sometimes the middle, and sometimes the top.
Seyyathāpi, bhikkhave, daṇḍo uparivehāsaṃ khitto sakimpi mūlena nipatati, sakimpi majjhena nipatati, sakimpi antena nipatati;

Therefore, as I suspected, the word "mūla" might be closer to the subject/thing itself than being a distant preceding cause. In SN 15.9, it is the "bottom/base" of a stick (rather than a more distant cause, such as tree, tool or carpenter that made the stick). This appears apparent in SN 4.24 which says:

“Having dug up entirely the root of sorrow, Guiltless, I meditate free from sorrow. Having cut off all greedy urge for existence, I
  meditate taintless, O kinsman of the negligent!”

Again, Snp 4.14 is about a very close cause rather than a distant cause:

One should completely extract the root of proliferation and reckoning— The notion, “I am the thinker”.

AN 10.58 says: 

Wholesome zeal (chanda) is the root of all dhamma practise.

This says without zeal (chanda), dhamma practises will be ineffective, similar to how a car cannot drive without fuel. 
I think 'mūla' is a characteristic or cause of a thing that is very closely tied to the thing. Therefore, 'ignorance' is probably too distant a cause to be the 'mūla' of suffering because what makes suffering burn is the craving, attachment & egoism. 
Therefore, the "root" or "base" of suffering is craving & delight. The "trunk" of suffering is "becoming & ego-birth". The "branches & leaves" of suffering are "ego-aging-death, sorrow, lamentation, pain, grief & despair". 


"Ignorance" is the first cause/leader of all unskilful qualities, which includes attachment. 

Avijjā, bhikkhave, pubbaṅgamā akusalānaṃ dhammānaṃ samāpattiyā..
Monks, ignorance is the leader/foreunner in the attainment of unskillful qualities...
SN 45.1

Purimā, bhikkhave, koṭi na paññāyati avijjāya: ‘ito pubbe avijjā nāhosi, atha pacchā samabhavī’ti
Bhikkhus, this is said: ‘A first point of ignorance, bhikkhus, is not seen such that before this there was no ignorance and afterward it came into being.’
AN 10.61


user13709: Thanks to SuttaCentral and all of the other answers here, I would propose the following:
A root can be seen. Ignorance is blindness. From Root of Existence, in our practice we should perceive the root of suffering as craving, delight, relishing and attachment. For this reason, saying that "ignorance is the root of suffering" is misleading in the context of MN1 because one cannot see one's own ignorance. Although the suttas do not themselves declare ignorance as the root of suffering, the commentaries do (Buddhaghosa, Bodhi)
From Dependent Origination we have "Ignorance is the condition for...old age and death, sorrow, lamentation, pain, sadness, and distress". I.e., suffering originates in ignorance. For this reason it is misleading to say that "ignorance is not the root of suffering". Specifically:

When ignorance fades away...this entire mass of suffering ceases

Delight is the root of suffering. Ignorance planted the seed. Look for the root and do not plant the wrong seed.
Regarding the original question on ignorance and is/is-not the root of suffering:
The phrase root of suffering is a key phrase in Buddhism often associated by all directly with the words of the Buddha. For me to utter either of those phrases would therefore be an indulged conceit of representing myself as The Blessed One.
However, if any Buddha past or present should utter these phrases, that would be their prerogative. I do not consider it mine.
The issue here is not only about right view. Dependent origination is understood as such. The issue here is also right speech. Literally: Can one assert ...(a phrase)...
The issue of right speech and our diligence in quoting the Buddha is that in our careless discussion:

the discourses spoken by the Realized One—deep, profound, transcendent, dealing with emptiness—will disappear.



user471: Let me introduce you to the old South Indian Monkey Trap (from this article):

In Zen And The Art Of Motorcycle Maintenance, Robert Pirsig’s
  bonkers-but-brilliant philosophical novel that turns 40 this year, he
  describes “the old South Indian Monkey Trap”. ... The trap
  “consists of a hollowed-out coconut, chained to a stake. The coconut
  has some rice inside which can be grabbed through a small hole”. The
  monkey’s hand fits through the hole, but his clenched fist can’t fit
  back out. “The monkey is suddenly trapped.” But not by anything
  physical. He’s trapped by an idea, unable to see that a principle that
  served him well – “when you see rice, hold on tight!” – has become
  lethal.

The monkey needs to let go of the rice in order to free himself from his suffering. The way to end his suffering, is to end his craving for rice. He got stuck in the trap in the first place due to his craving for rice.
But in order to end his craving for rice, he must first understand how his hand is stuck inside the coconut. When the monkey overcomes his ignorance about how the trap works, he would let go of his craving for rice, and release his clenched fist. With this, he would be free from his suffering.
So, the root of the monkey's misery is craving, and not ignorance, as stated in SN 22.31:

“And what, bhikkhus, is misery? Form is misery; feeling is misery;
  perception is misery; volitional formations are misery; consciousness
  is misery. This is called misery.
“And what, bhikkhus, is the root of misery? It is this craving that
  leads to renewed existence, accompanied by delight and lust, seeking
  delight here and there; that is, craving for sensual pleasures,
  craving for existence, craving for extermination. This is called the
  root of misery.”

But to uproot craving, the monkey must first overcome his ignorance.
If the monkey had ignorance of the working of the trap, but if he had no craving, he would not get stuck in the trap. If the monkey had craving but did not have ignorance, he could still neglect his knowledge and get caught in the trap, due to greed and clinging. Hence, craving is the root of suffering, and not ignorance.

(Illustration above: Paul Thurlby for the Guardian)

13709: <p><a href="https://suttacentral.net/search?query=%22root%20of%20suffering%22" rel="nofollow noreferrer">Searching the Pali Canon for the "root of suffering",</a> we find the direct  definition only occurs in a few suttas:</p>

<ul>
<li>delight is the root of suffering (<a href="https://suttacentral.net/mn1/en/bodhi" rel="nofollow noreferrer">MN1</a>)</li>
<li>attachment is the root of suffering (<a href="https://suttacentral.net/mn105/en/sujato" rel="nofollow noreferrer">MN105</a>, <a href="https://suttacentral.net/mn66/en/sujato" rel="nofollow noreferrer">MN66</a>)</li>
<li>desire is the root of suffering ([MN42.11])</li>
<li>what is greed? ... that which is...root of suffering (<a href="https://suttacentral.net/vb17/en/thittila" rel="nofollow noreferrer">Vb17</a>)</li>
</ul>

<p>We also have that ignorance is simply one product of dependent origination (SN 22.81):</p>

<blockquote>
  <p><a href="https://suttacentral.net/sn22.81/en/sujato" rel="nofollow noreferrer">And that craving, that feeling, that contact, and that <strong>ignorance</strong> are also impermanent, conditioned, and dependently originated</a>.</p>
</blockquote>

<p>Ignorance does indeed result in suffering, but to claim it as the <em>root of suffering</em> feels a bit misleading. </p>

<p><strong>Can one assert “ignorance is the root of suffering?”</strong> </p>

<p><strong>Can one assert “ignorance is NOT the root of suffering?”</strong></p>

<p>In your answers, kindly include actual sutta references, preferably from the Pali Canon. This is necessary to avoid arguing about personal interpretation since supported translations are provided by ordained and well-respected monks. As a Sangha, we have to respect and uphold the Dhamma. </p>

<p></p>
 11541: <p>It is true that craving, feeling, contact, and ignorance are impermanent, conditioned, and dependently originated.
Coming together of Ignorance and Contact gives rise to Craving which in turn gives rise to Suffering. If we abandon Ignorance or Contact or Craving or Feeling completely, the Suffering will cease. Therefore in a sense all of the above factors of dependent origination can be called the root of suffering. </p>
 8157: <p>The question requires understanding exactly what the word "mūla" ("root") is meant to mean in terms of its general usage (which I cannot answer at this current time and requires a contextual analysis of the texts). However, given "attachment" actually is suffering itself, the word "root" may not mean a "preceding cause" ("hetu") but be something much closer to the subject/thing. </p>

<blockquote>
  <p><em>Delight in feelings is attachment - MN 38</em></p>
  
  <p><em>In short, suffering is the five aggregates attached to - SN 56.11</em></p>
  
  <p><em>Conceiving 'self' is an arrow, disease, cancer - MN 140</em></p>
  
  <p><em>Resolved on 'my self'... is suffering arising... SN 12.15</em></p>
  
  <p><em>View of 'a being'... is suffering arising... SN 5.10</em></p>
</blockquote>

<p>In SN 42.11, 'root' is used as a preceding cause; although '<em>chando</em>' is not as exact as '<em>tanha</em>': </p>

<blockquote>
  <p><em>For desire is the root of suffering. Chando hi mūlaṃ dukkhassa.</em></p>
</blockquote>

<p>In MN 22, something that is essentially 'causeless', namely, ignorance, is cut off at its root: </p>

<blockquote>
  <p><em>Herein the monk has abandoned ignorance, has cut it off at the root..</em></p>
  
  <p><em>Abandoned the round of re-births, leading to renewed existence; he has cut it off at the root...</em></p>
  
  <p><em>Abandoned craving, has cut it off at the root...</em></p>
  
  <p><em>Abandoned the five lower fetters, has cut them off at the root...</em></p>
  
  <p><em>Abandoned the conceit of self, has cut it off at the root...</em></p>
</blockquote>

<p>The contextual analysis becomes more clear with SN 15.9, which says:</p>

<blockquote>
  <p><em>Suppose a stick was tossed up in the air. Sometimes it’d fall on its <strong>bottom</strong>, sometimes the middle, and sometimes the top.</em></p>
  
  <p><em>Seyyathāpi, bhikkhave, daṇḍo uparivehāsaṃ khitto sakimpi <strong>mūlena</strong> nipatati, sakimpi majjhena nipatati, sakimpi antena nipatati;</em></p>
</blockquote>

<p>Therefore, as I suspected, the word "mūla" might be closer to the subject/thing itself than being a distant preceding cause. In SN 15.9, it is the "bottom/base" of a stick (rather than a more distant cause, such as tree, tool or carpenter that made the stick). This appears apparent in SN 4.24 which says:</p>

<blockquote>
  <p><em>“Having dug up entirely the root of sorrow, Guiltless, I meditate free from sorrow. Having cut off all greedy urge for existence, I
  meditate taintless, O kinsman of the negligent!”</em></p>
</blockquote>

<p>Again, Snp 4.14 is about a very close cause rather than a distant cause:</p>

<blockquote>
  <p><em>One should completely extract the root of proliferation and reckoning— The notion, “I am the thinker”.</em></p>
</blockquote>

<p>AN 10.58 says: </p>

<blockquote>
  <p><em>Wholesome zeal (chanda) is the root of all dhamma practise.</em></p>
</blockquote>

<p>This says without zeal (chanda), dhamma practises will be ineffective, similar to how a car cannot drive without fuel. </p>

<p>I think 'mūla' is a characteristic or cause of a thing that is very closely tied to the thing. Therefore, 'ignorance' is probably too distant a cause to be the 'mūla' of suffering because what makes suffering burn is the craving, attachment &amp; egoism. </p>

<p>Therefore, the "<em>root</em>" or "<em>base</em>" of suffering is craving &amp; delight. The "<em>trunk</em>" of suffering is "becoming &amp; ego-birth". The "<em>branches &amp; leaves</em>" of suffering are "<em>ego-aging-death, sorrow, lamentation, pain, grief &amp; despair</em>". </p>

<hr>

<hr>

<p>"Ignorance" is the first cause/leader of all unskilful qualities, which includes attachment. </p>

<blockquote>
  <p><em>Avijjā, bhikkhave, pubbaṅgamā akusalānaṃ dhammānaṃ samāpattiyā..</em></p>
  
  <p><em>Monks, ignorance is the leader/foreunner in the attainment of unskillful qualities...</em></p>
  
  <p><a href="https://www.accesstoinsight.org/tipitaka/sn/sn45/sn45.001.than.html" rel="nofollow noreferrer"><em>SN 45.1</em></a></p>
  
  <hr>
  
  <p><em>Purimā, bhikkhave, koṭi na paññāyati avijjāya: ‘ito pubbe avijjā nāhosi, atha pacchā samabhavī’ti</em></p>
  
  <p><em>Bhikkhus, this is said: ‘A first point of ignorance, bhikkhus, is not seen such that before this there was no ignorance and afterward it came into being.’</em></p>
  
  <p><em>AN 10.61</em></p>
</blockquote>
 13709: <p>Thanks to <a href="https://discourse.suttacentral.net/t/ignorance-and-the-root-of-suffering/10165" rel="nofollow noreferrer">SuttaCentral</a> and all of the other answers here, I would propose the following:</p>

<p>A root can be seen. Ignorance is blindness. From <a href="https://suttacentral.net/mn1/en/sujato" rel="nofollow noreferrer">Root of Existence</a>, in our practice we should perceive the root of suffering as craving, delight, relishing and attachment. For this reason, saying that "ignorance is the root of suffering" is misleading in the context of <a href="https://suttacentral.net/mn1/en/sujato" rel="nofollow noreferrer">MN1</a> because one cannot see one's own ignorance. Although the suttas do not themselves declare ignorance as the root of suffering, the commentaries do (<a href="https://www.accesstoinsight.org/lib/authors/nanamoli/PathofPurification2011.pdf" rel="nofollow noreferrer">Buddhaghosa</a>, <a href="http://www.londonbuddhistvihara.org/Talks/Abhidhamma_Course/anuruddha_abhidhammattha-sangaha_b.pdf" rel="nofollow noreferrer">Bodhi</a>)</p>

<p>From <a href="https://suttacentral.net/sn12.1/en/sujato" rel="nofollow noreferrer">Dependent Origination</a> we have "Ignorance is the condition for...old age and death, sorrow, lamentation, pain, sadness, and distress". I.e., suffering originates in ignorance. For this reason it is misleading to say that "ignorance is not the root of suffering". Specifically:</p>

<blockquote>
  <p><a href="https://suttacentral.net/sn12.1/en/sujato" rel="nofollow noreferrer">When ignorance fades away...this entire mass of suffering ceases</a></p>
</blockquote>

<p><a href="https://suttacentral.net/mn1/en/bodhi" rel="nofollow noreferrer">Delight is the root of suffering</a>. Ignorance planted the seed. Look for the root and do not plant the <a href="https://suttacentral.net/an10.104/en/thanissaro" rel="nofollow noreferrer">wrong seed</a>.</p>

<p>Regarding the original question on <em>ignorance</em> and <em>is/is-not the root of suffering</em>:</p>

<p>The phrase <strong>root of suffering</strong> is a key phrase in Buddhism often associated by all directly with the words of the Buddha. For me to utter either of those phrases would therefore be an indulged conceit of representing myself as The Blessed One.</p>

<p>However, if any Buddha past or present should utter these phrases, that would be their prerogative. I do not consider it mine.</p>

<p>The issue here is not only about right view. Dependent origination is understood as such. The issue here is also <em>right speech</em>. Literally: <em>Can one assert ...(a phrase)...</em></p>

<p>The issue of right speech and our diligence in quoting the Buddha is that in our careless discussion:</p>

<blockquote>
  <p><a href="https://suttacentral.net/sn20.7/en/sujato" rel="nofollow noreferrer">the discourses spoken by the Realized One—deep, profound, transcendent, dealing with emptiness—will disappear.</a></p>
</blockquote>

<p></p>
 471: <p>Let me introduce you to the old South Indian Monkey Trap (from <a href="https://www.theguardian.com/lifeandstyle/2014/nov/14/how-to-avoid-monkey-trap-oliver-burkeman" rel="nofollow noreferrer">this article</a>):</p>

<blockquote>
  <p>In <a href="https://rads.stackoverflow.com/amzn/click/0060589469" rel="nofollow noreferrer">Zen And The Art Of Motorcycle Maintenance</a>, Robert Pirsig’s
  bonkers-but-brilliant philosophical novel that turns 40 this year, he
  describes “the old South Indian Monkey Trap”. ... The trap
  “consists of a hollowed-out coconut, chained to a stake. The coconut
  has some rice inside which can be grabbed through a small hole”. The
  monkey’s hand fits through the hole, but his clenched fist can’t fit
  back out. “The monkey is suddenly trapped.” But not by anything
  physical. He’s trapped by an idea, unable to see that a principle that
  served him well – “when you see rice, hold on tight!” – has become
  lethal.</p>
</blockquote>

<p>The monkey needs to let go of the rice in order to free himself from his suffering. The way to end his suffering, is to end his craving for rice. He got stuck in the trap in the first place due to his craving for rice.</p>

<p>But in order to end his craving for rice, he must first understand how his hand is stuck inside the coconut. When the monkey overcomes his ignorance about how the trap works, he would let go of his craving for rice, and release his clenched fist. With this, he would be free from his suffering.</p>

<p>So, the root of the monkey's misery is craving, and not ignorance, as stated in <a href="https://suttacentral.net/sn22.31/en/bodhi" rel="nofollow noreferrer">SN 22.31</a>:</p>

<blockquote>
  <p>“And what, bhikkhus, is misery? Form is misery; feeling is misery;
  perception is misery; volitional formations are misery; consciousness
  is misery. This is called misery.</p>
  
  <p>“And what, bhikkhus, is the root of misery? It is this craving that
  leads to renewed existence, accompanied by delight and lust, seeking
  delight here and there; that is, craving for sensual pleasures,
  craving for existence, craving for extermination. This is called the
  root of misery.”</p>
</blockquote>

<p>But to uproot craving, the monkey must first overcome his ignorance.</p>

<p>If the monkey had ignorance of the working of the trap, but if he had no craving, he would not get stuck in the trap. If the monkey had craving but did not have ignorance, he could still neglect his knowledge and get caught in the trap, due to greed and clinging. Hence, craving is the root of suffering, and not ignorance.</p>

<p><a href="https://www.theguardian.com/lifeandstyle/2014/nov/14/how-to-avoid-monkey-trap-oliver-burkeman" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YNJMJ.jpg" alt="The old South Indian Monkey Trap"></a>
(Illustration above: Paul Thurlby for the Guardian)</p>
