But the event will still give Democrats a first payoff from their purge of lawmakers targeted by sexual harassment allegations if Trump repeats his endorsement of the scandal-rocked Moore.
The sweeping away of Sen. Al Franken and Rep. John Conyers this week after claims of inappropriate behavior against them cleared the way for Democrats to argue that their party takes the #MeToo movement seriously, and to charge that the GOP offers a haven to alleged perpetrators.
"I, of all people, am aware that there is some irony in the fact that I am leaving while a man who has bragged on tape about his history of sexual assault sits in the Oval Office and a man who has repeatedly preyed on young girls campaigns for the Senate with the full support of his party," Franken said Thursday, referring to Trump and Moore.
The Democrats' strategy will go into overdrive if Moore creates a massive political headache for GOP leaders in Washington by winning the special election on Tuesday -- but Trump's rally gives it an early test run.
Trump will hold one of his boisterous, colorful and unpredictable rallies in Pensacola, the waterfront city in the Florida panhandle that shares a media market with Mobile, Alabama.
The combination of a rocking Friday night crowd, the end of a contentious political week, and the freedom Trump experiences outside Washington could cause the President to barnstorm into controversial political territory after a week in which his tweeting has been quite restrained by his own wild standards.
Pensacola offers Trump a veneer of deniability that he is campaigning directly for the controversial Moore, but also allows him to reach out directly to his grassroots voters in Alabama, in a bid to swell turnout in Tuesday's election.
Trump is wildly popular in the deep red state -- he crushed his rivals in the 2016 GOP primary by more than 20% and beat Hillary Clinton by nearly 30 points there in the general election. So even if he is able to motivate a couple of thousand Republicans tempted to skip the election because of the allegations against Moore, he could make a difference in the former judge's tight race with Democrat Doug Jones.
Trump caused uproar last week when he told reporters that the Republican candidate "totally denies" the allegations against him -- even after GOP leaders in Washington effectively disowned their candidate and said that they believed his accusers.
Trump went all in this week, arguing that he could not afford for the already narrow two-vote Republican majority in the Senate to be further whittled down.
"Democrats refusal to give even one vote for massive Tax Cuts is why we need Republican Roy Moore to win in Alabama. We need his vote on stopping crime, illegal immigration, Border Wall, Military, Pro Life, V.A., Judges 2nd Amendment and more. No to Jones, a Pelosi/Schumer Puppet!" Trump tweeted on Monday.
"Putting Pelosi/Schumer Liberal Puppet Jones into office in Alabama would hurt our great Republican Agenda of low on taxes, tough on crime, strong on military and borders...& so much more."
Moore has been accused of initiating sexual contact with a 14-year-old girl, sexually assaulting a 16-year-old and pursuing relationships with teenage girls -- all while he was in his 30s. He has denied the claims.
The White House has responded to criticism of Trump's effective endorsement of Moore by saying that the President remains concerned about the allegations.
On Thursday, White House press secretary Sarah Sanders said: "We think that the allegations are troubling and that ultimately this is something that the people of Alabama should decide."
Sanders shrugged off Franken's barb from his resignation speech, saying Trump's comments caught on an "Access Hollywood" tape released last year boasting about sexually assaulting women were old news.
"The President addressed the comments back during the campaign," Sanders said Thursday
. "We feel strongly that the people of this country also addressed that when they elected Donald Trump to be president."