Donald Trump went to Huntsville, Alabama last night to hold a rally for embattled GOP incumbent Luther Strange, who is facing an uphill battle to become the GOP nominee in a runoff election on Tuesday. 

Strange is being challenged by former judge Roy Moore, who holds an 8-point lead in the last poll taken.

The Hill:

A new poll shows former state Supreme Court Justice Roy Moore (R) leading Sen. Luther Strange (R) by eight points just days before the Republican primary for the Alabama Senate.

Moore, the favorite on the right, took 54 percent support in a Fox10 News/Strategy Research survey, while the incumbent Strange got 46 percent.

The race has become a proxy war between the conservative grass roots and the establishment.

Moore is supported by former Trump campaign chief Steve Bannon, as well as several prominent grassroots conservatives.

Former Alaska Gov. Sarah Palin (R) headlined a pro-Moore rally with Breitbart News writer and former White House aide Sebastian Gorka on Thursday night.

Breitbart and its chairman Stephen Bannon, who until recently was Trump’s chief strategist in the White House, are squarely behind Moore. A pro-Trump outside group called Great America Alliance is going up with pro-Moore ads this weekend during the Alabama football game.

Meanwhile, Strange’s allies, including a super PAC aligned with Senate Majority Leader Mitch McConnell (R-Ky.), have poured tens of millions of dollars into the race. There are no recent polls that show Strange in the lead.

Trump's own HUD secretary, Ben Carson, has broken with the president to side with Moore, who has run a slashing campaign against Washington and has used Strange as a whipping boy for the establishment.

Trump's natural inclination would be to support Moore.  But the president was convinced by the RNC and several senators in the Republican leadership to go to Alabama and support the incumbent.

CNN:

At a raucous rally in Huntsville, the President warned that that former judge Moore could lose the state's Senate special election to a Democrat – but if Strange, who already holds the Senate seat, wins Tuesday's primary, "it's over."

With the endorsement, Trump took what he admitted was a risk – pumping his own political capital into an effort to carry Strange to victory, even though a Moore win could put a dent in Trump's influence.

Trump said he "might've made a mistake, I'll be honest," by wading into the race.

But, he said, "Luther's going to win easily and Roy is going to have a hard time winning" a December general election against Democrat Doug Jones.

Trump's comments about electability came as he acknowledged that Senate Republicans can't spare a single vote. He pointed to Sen. John McCain's announcement Friday that he opposes the latest GOP health care bill – effectively ending the party's chances for now at repealing Obamacare.

His decision to visit Alabama and campaign for Strange, Trump said, was all about loyalty.

The President bluntly told the crowd that when he was handed a list of 10 senators he needed to lobby to support his health care effort, some insisted on dinners and meetings with their families before Trump could win them over.

But when he called Strange, the new senator appointed in February to replace Attorney General Jeff Sessions, said, in Trump's retelling: "Sir, don't even waste your time talking anymore. You have a lot of business to do. You have my vote."

Trump said he told first lady Melania Trump about the call. "I went home and told my wife, that's the coolest thing that's happened to me in six months."

Trump also defended Strange against Moore's accusations that he is doing Senate Majority Leader Mitch McConnell's bidding, saying that Strange has only known McConnell for months. The charges have stemmed from a pro-McConnell super PAC spending $9 million to boost Strange.

Trump and McConnell have butted heads as Republicans' frustration has mounted over the party's failure to repeal Obamacare and enact other Trump agenda items, with Trump publicly blasting the Senate leader on Twitter repeatedly in recent weeks.

In truth, "electability" is not an issue in Alabama.  Even if Moore prevails, he is likely to coast to victory in the special December election being held to replace now-attorney general Jeff Sessions.  Alabama is one of the most Republican states in the union, and with turnout expected to be minimal, the Democrats will be hard pressed to come close to pulling the upset.

Bannon is using Alabama as a test case for his plan to challenge GOP incumbents across the country.  The factors that have led to Moore's ascendancy may not be present in many other states, but the energy and enthusiasm that will be generated among the base with a Moore victory could make life difficult for other establishment Republicans.

Trump is risking his popularity with his base to gin up support for Strange.  It will be interesting to see if Trump can transfer his popularity with grassroots conservatives to an incumbent who many on the right believe is part of the problem in Washington.