As Deputy Leader, Scullin excelled in taking the case to the government.
Throughout 1927 Scullin earned particular acclaim in keeping the ageing Bruce government to account on economic and financial matters.
A series of speeches by Scullin that year on the Government's mishandling of the economy, and the generally dangerous trajectory of Commonwealth financial policy, predicted catastrophe.
He accused the government of spending too much, borrowing too much from overseas sources, and not rectifying a worrying excess of imports over exports: a three-part recipe for disaster.
This alarming analysis of the Australian economy would prove to be correct within three years, however relatively few paid attention to Scullin's warning at the time, nor the prescient 1927 volume The Boom of 1890 – And Now by E.O.G. Shann, on which Scullin based many of his arguments.

In March 1928, Matthew Charlton resigned as federal Labor leader and was replaced by Scullin in a unanimous motion, although some had their eye on newcomer Ted Theodore as a more promising replacement.
The ensuing contest over the position of Deputy Leader saw Theodore denied once again in a close vote, foreshadowing some of the future controversy he would stir up within the party under Scullin.

Scullin led Labor at the 1928 election.
He visited widely around the country, and made especial focus on Western Australia, Tasmania and Queensland – states where the Labor party's fortunes had greatly declined in previous years.
Scullin was well received and made ground in these areas, as well as in rural districts to counteract the increasingly urban nature of Labor.
 Labor managed to take eight seats, significantly reducing the Coalition's previously large majority.
 This was due to a swing against the government rather than a swing towards Labor, but was still enough to put Labor within striking distance of winning the next election.
 Although Labor came up well short of forming government, the campaign was viewed as a success and Scullin's reputation remained intact as leader.

1929 was dogged by industrial disputes, the worst of which occurred within the waterfront, timber and coalmining sectors.
The Bruce government struggled to manage these episodes – its proposal by referendum for greater Commonwealth industrial powers had been rejected in 1926.
After months of deadlock and protests over decisions of the Federal Arbitration Court, Bruce reversed course entirely by proposing that the Commonwealth dismantle federal arbitration and hand industrial matters back entirely to the states.
The proposal was a radical departure from one of the pillars of the so-called "Australian settlement", and several MPs, led by former PM Billy Hughes, ultimately voted against the government and forced Bruce to seek an additional mandate from the people, at the 1929 election.
Crucially, it would be a House-only election as the 1925 Senate term had not expired.
Just 9 months after the previous campaign, Australia was in campaign mode once more.
Amidst a background of industrial strife and heavy handed government proposals to deal with it, Scullin, who preached conciliation and negotiation between the parties, seemed the moderate choice, despite the more radical stances otherwise held by Labor.
Fighting on their home territory and in favour of what was a still popular status-quo in industrial relations law, Scullin and Labor romped home in the polls, winning 46 seats in the 75 seat chamber, the most they had ever won at the time.
 Labor even managed to oust Bruce in his own seat.
 The party was jubilant and Scullin enthusiastically accepted commission to become Prime Minister.
He was to be Australia's first Catholic prime minister.
As Deputy Leader, Scullin excelled in taking the case to the government. Throughout 1927 Scullin earned particular acclaim in keeping the ageing Bruce government to account on economic and financial matters. A series of speeches by Scullin that year on the Government's mishandling of the economy, and the generally dangerous trajectory of Commonwealth financial policy, predicted catastrophe. He accused the government of spending too much, borrowing too much from overseas sources, and not rectifying a worrying excess of imports over exports: a three-part recipe for disaster. This alarming analysis of the Australian economy would prove to be correct within three years, however relatively few paid attention to Scullin's warning at the time, nor the prescient 1927 volume The Boom of 1890 – And Now by E.O.G. Shann, on which Scullin based many of his arguments.
In March 1928, Matthew Charlton resigned as federal Labor leader and was replaced by Scullin in a unanimous motion, although some had their eye on newcomer Ted Theodore as a more promising replacement. The ensuing contest over the position of Deputy Leader saw Theodore denied once again in a close vote, foreshadowing some of the future controversy he would stir up within the party under Scullin.
Scullin led Labor at the 1928 election. He visited widely around the country, and made especial focus on Western Australia, Tasmania and Queensland – states where the Labor party's fortunes had greatly declined in previous years. Scullin was well received and made ground in these areas, as well as in rural districts to counteract the increasingly urban nature of Labor.  Labor managed to take eight seats, significantly reducing the Coalition's previously large majority.  This was due to a swing against the government rather than a swing towards Labor, but was still enough to put Labor within striking distance of winning the next election.  Although Labor came up well short of forming government, the campaign was viewed as a success and Scullin's reputation remained intact as leader.
1929 was dogged by industrial disputes, the worst of which occurred within the waterfront, timber and coalmining sectors. The Bruce government struggled to manage these episodes – its proposal by referendum for greater Commonwealth industrial powers had been rejected in 1926. After months of deadlock and protests over decisions of the Federal Arbitration Court, Bruce reversed course entirely by proposing that the Commonwealth dismantle federal arbitration and hand industrial matters back entirely to the states. The proposal was a radical departure from one of the pillars of the so-called "Australian settlement", and several MPs, led by former PM Billy Hughes, ultimately voted against the government and forced Bruce to seek an additional mandate from the people, at the 1929 election. Crucially, it would be a House-only election as the 1925 Senate term had not expired. Just 9 months after the previous campaign, Australia was in campaign mode once more. Amidst a background of industrial strife and heavy handed government proposals to deal with it, Scullin, who preached conciliation and negotiation between the parties, seemed the moderate choice, despite the more radical stances otherwise held by Labor. Fighting on their home territory and in favour of what was a still popular status-quo in industrial relations law, Scullin and Labor romped home in the polls, winning 46 seats in the 75 seat chamber, the most they had ever won at the time.  Labor even managed to oust Bruce in his own seat.  The party was jubilant and Scullin enthusiastically accepted commission to become Prime Minister. He was to be Australia's first Catholic prime minister.
James Scullin