Alabama senator endorses Trump: Is that a big deal?

Underscoring Donald Trump’s tough rhetoric on immigration, Sen. Jeff Sessions (R) of Alabama became the first senator to endorse the real estate mogul as the top Republican contender in the presidential election.

Appearing before a crowd of thousands in Madison, Ala., Senator Sessions wore a red "Make America Great Again" hat while touting the business magnate. His de jure support quickly follows the endorsement of New Jersey Gov. Chris Christie and former Arizona Gov. Jan Brewer. Together, these three signify parts of the GOP establishment throwing their weight behind Trump, who hasn’t exactly been the favorite of the RNC.

“While Christie brings an outside-the-beltway gravitas and perspective,” as NBC’s Ali Vitali writes, “Sessions' backing is the first major sign Trump is earning the faith of true conservatives on Capitol Hill.”

Sessions, perhaps the most conservative member of the Senate, choosing Trump can also be seen as a major blow to Texas Sen. Ted Cruz. Senator Cruz is one of Trump’s most formidable opponents, and has tried to set himself apart from the businessman by questioning his conservative credentials.

"Politicians have promised for 30 years to fix illegal immigration. Have they done it? Donald Trump will do it," Mr. Sessions said at the Madison City Schools Stadium. “I’ve told Donald Trump this isn’t a campaign, this is a movement.” 

Trump returned the compliment.

“When I talk about immigration and when I talk about illegal immigration and all the problems with crime and everything else, I think of a great man,” Trump said of Sessions in Madison. 

Meanwhile, as Super Tuesday approaches, Mr. Cruz has tried to characterize Trump's stance on immigration reform as weak, saying his plan contains “amnesty.”

Immigration is one of the most vital points in Trump’s campaign. He first made waves when he accused Mexican immigrants of being criminals and rapists. Later, he called for the mass deportation of 12 million undocumented immigrants living in the US and vowed to amplify border security with to a massive wall alongside the US-Mexico border.

Many of his critics have deemed this plan unrealistic, though Sessions’ position as the chairman of the Senate subcommittee on immigration helps legitimize it.

“That is so great. You know, he’s an incredible guy,” Trump added after Sessions gave his endorsement. “I'm becoming mainstream. All these people are now endorsing me.”

Trump highlighted the fact that Sessions, a veteran of Congress for nearly 20 years, had – until now – yet to endorse a presidential candidate. "When I get Jeff Sessions, that means a lot to me. That means a lot. That's a biggie, especially since he's never done it before,” he said.

But Cruz and Sessions have also been close in recent years. Sessions appeared alongside the junior senator from Texas last December in Daphne, Ala., The Washington Post reports, and has defended Cruz when critics accused him of once supporting a path to legal status for undocumented immigrants.

Trump, however, ultimately won Sessions over. The two began meeting early last year to discuss the candidate’s platform on immigration policy. Sessions first appeared on stage next to Trump last summer in Mobile, Ala.

The two men also met in September after Trump appeared at a rally protesting the nuclear deal with Iran, joined by 2008 GOP vice-presidential nominee and former Alaska Gov. Sarah Palin. The latter has since endorsed Trump as well.

But not every Republican senator is head-over-heels with Trump. Nebraska's Ben Sasse said – explicitly – late Sunday that he will not back Trump if he wins the nomination.

"If Trump becomes the Republican nominee, my expectation is that I'll look for some 3rd candidate – a conservative option, a constitutionalist," Senator Sasse writes on Twitter.

And while endorsements can offer a campaign boost, they aren't necessarily game changers. In the past two weeks, Rubio has garnered endorsements of four governors and 20 members of Congress – more than all of his Republican rivals combined. 

But Rubio is still trailing Trump in the polls.