Republican Presidential candidate Ted Cruz will pick up his first Senate endorsement Thursday when Sen Mike Lee, a Republican from Utah, will announce he's backing Cruz, sources familiar with the decision tell NBC News. 
 
 The endorsement comes just days before key contests in Ohio and Florida, and it gives the Texas Republican momentum after winning Idaho on Tuesday and receiving the endorsement of former Republican candidate Carly Fiorina on Wednesday. 
 
 Lee was one of only three GOP senators who missed today's Senate vote on a bill to aid those affected by opioid abuse. The other two were Sens Rubio and Cruz. 
 
 While Cruz has become a divisive figure within the Republican conference in the Senate, Lee is considered one of his only allies, and at a recent campaign stop Cruz said Lee was "someone I love like a brother." 
 
 But Lee has not endorsed until today, instead choosing to campaign for both Cruz and Senator Marco Rubio, a Republican from Florida. 
 
 "I've got two really good friends in this race," Lee told reporters at a Cruz campaign stop in South Carolina in February, "Any one of them running alone would have gotten my endorsement a long time ago." 
 
 The endorsement of Cruz over Rubio before Tuesday's primary in Rubio's home state of Florida may be a sign that Republicans see Cruz as the candidate who has the best chance to combat Donald Trump. 
 
 Rubio's campaign has failed to meet expectations in recent weeks, and the Florida Senator was awarded zero delegates on Tuesday, when four states held contests in the Republican race for the nomination. While Rubio has the backing of 14 Senate Republicans, some of them publicly have express concern that he may need to exit the race if he fails to win Florida next week. 
 
 "I'm not going to give him any strategy or tell him what to do or what not to do, I'll let his people do that," Senator Dean Heller (R-NV), who has endorsed Rubio, told reporters, "But I think he's going to have to really rethink moving forward after Florida." 
 
 But Heller told reporters that if Rubio dropped out of the race he could see himself supporting Cruz if he became the nominee. 
 
 "Most certainly, most certainly," Heller said when asked if he could support Cruz, "I don't want to weigh in on who's best or who's not best, but I could see myself as a Cruz supporter." 
 
 "You know, as a supporter of Bush, and now a supporter of Rubio, I think the general public as a whole has been pretty convincing that they want something very different than what we have today," Heller said. 
 
 Sen Lindsey Graham, a Republican Senator from South Carolina who also ran for President this year before dropping out in December, said he believes Lee's endorsement of Cruz could help him show he's a viable alternative to Donald Trump. 
 
 "It shows that people see Ted's campaign as becoming the most viable," Graham told NBC News, "I just think he's becoming the most viable alternative to Trump." ||||| Carly Fiorina endorsed Republican presidential candidate Sen. Ted Cruz Rafael (Ted) Edward CruzCruz’s Democratic challenger officially files for Senate We need to know how far Russia’s attack on American sovereignty really goes Trump, Senate GOP at odds over Roy Moore MORE (Texas) at a Miami rally on Wednesday, praising him as a political outsider. 
 
 "Ted Cruz has always been a constitutional conservative," the former Hewlett-Packard CEO said, describing Cruz as "a fearless fighter and reformer." 
 
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 Fiorina ended her own White House bid in mid-February after a poor showing in early-voting states. 
 
 Her campaign was known for her harsh criticism of Democratic presidential front-runner Hillary Clinton Hillary Diane Rodham ClintonSenate panel scraps deadline for Kushner to turn over documents McCain on Clinton's memoir: 'What’s the f---ing point?' Re-labeling North Korea a terrorist state a long time coming MORE. 
 
 "The truth is that Donald Trump Donald John TrumpWarren fundraises off of Trump's 'Pocahontas' jab Dem senator slams Trump's 'moral authority' after 'Pocahontas' remark Bill Press: Religion flunks morality MORE and Hillary Clinton are two sides of the same coin," Fiorina said Wednesday, ripping the GOP front-runner. 
 
 "They aren't going to reform the system. They are the system." 
 
 Fiorina noted that many in the Republican Party are "horrified by Donald Trump." 
 
 "I'm one of them," she added, describing Cruz as "the only guy who can beat Donald Trump." 
 
 "Ted Cruz has always been a constitutional conservative," Fiorina said, adding that he "didn’t care if he got invited to the cocktail parties in D.C." 
 
 Cruz complimented Fiorina as an "incredible business leader" in a press conference shortly after the endorsement. 
 
 "Her campaign for president impressed people all over this country, with her intelligence, knowledge, expertise ... with her ability to champion common sense conservative principles," Cruz said. 
 
 He pointed to Fiorina's support as "one more manifestation of what has been played out, as the one campaign that has demonstrated that can and repeatedly has beaten Donald Trump." 
 
 Cruz reiterated that rivals Marco Rubio Marco Antonio RubioFranken seeks to head off calls for resignation GOP tax agenda is a grave threat to people in poverty Rubio: Al Franken 'should consider resigning' MORE and John Kasich should "prayerfully reflect" and consider coalescing behind his campaign so he can go head-to-head with the front-runner. 
 
 Both candidates are pinning their hopes on their home states, which hold their winner-take-all contests on March 15. 
 
 "If you want to stop Donald Trump ... unify behind our campaign," Cruz said, adding that Republicans "don’t want to hand the election to Hillary Clinton on a silver platter" in November. 
 
 Her endorsement comes the day after Cruz's primary victory in Idaho. But Trump swept up most of the states Tuesday night, including Mississippi, dealing a blow to the Texas senator in an important Southern state. 
 
 This brings Cruz's total number of states won to seven, while Trump has 15. Rubio lags far behind with only one victory in Minnesota, as well as the territory of Puerto Rico. 
 
 While Cruz still trails Trump in the overall delegate count, his victory in Idaho gives him bragging rights as the only candidate to best the GOP front-runner on Tuesday. 
 
 Cruz continues to position himself as the viable alternative to Trump and has called on his fellow GOP rivals to coalesce behind him. 
 
 Fiorina spoke about the GOP pushing for comprehensive immigration reform and trying not to "rock the boat" by shying away from social issues after failing to win the White House in 2012. 
 
 "It is time now to unite behind the one man who can beat Donald Trump, who can beat Hillary Clinton, who can beat the D.C. cartel. It is time to unite behind Ted Cruz," Fiorina said to roaring cheers. 
 
 Fiorina's support provides Cruz a feisty surrogate, who captured the spotlight in early debates by knocking Clinton and going after Planned Parenthood. 
 
 Fiorina, who mostly shied away from criticizing Cruz directly while she was in the GOP race, did accuse the Texas senator in January of saying "whatever he needs to say to get elected." 
 
 — Last updated at 12:28 p.m.
– Politicians are getting behind Ted Cruz ... sort of: In a conference call to Minnesota supporters Wednesday that was mostly focused on explaining why he dropped out of the presidential race, Marco Rubio said that he hopes one of the GOP candidates still in the race will keep Donald Trump from becoming the nominee, the St. Paul Pioneer Press reports. He also said that Ted Cruz is "the only conservative left in the race" ... but he didn't actually endorse Cruz. (John Kasich is the only other non-Trump contender left.) Another senator and former 2016 presidential contender offered a similar non-endorsement of Cruz: Lindsey Graham tells CNN that he'll headline a fundraiser for Cruz on Monday, a meet-and-greet event during the AIPAC conference in DC. Why? "I think he's the best alternative to beat Donald Trump. I'm going to help Ted in any way I can," Graham explained. Buuuuut, "He's certainly not my preference," Graham added of Cruz. "But he's a reliable Republican, conservative, which I've had many differences with. John Kasich is the most viable general election candidate. I just don't see how John gets through the primary. This is an outsider year, and he is an insider." Graham, who has previously joked about how unpopular Cruz is among his fellow senators, added that Cruz is indeed "not well-liked," but said that even though "Senator Cruz would not be my first choice, I think he is a Republican conservative who I could support."