Donald Trump's influence loomed large as Americans voted Tuesday in midterm elections that could kickstart any bid to return to the White House in 2024 -- or, if his loyalists perform badly, derail it entirely.
While the former president's name is not on any ballot, scores of Republican candidates are carrying his personal endorsement in a litmus test for his popularity.
At the tail end of his final campaign rally on the eve of voting, Trump grabbed the national spotlight by saying he would make a "very big announcement" in Florida next week.
He teased the possible presidential run again Tuesday as he cast his vote in Palm Beach.
"I think Tuesday (November 15) will be a very exciting day for a lot of people, and I look forward to seeing you at Mar-e-Largo," Trump told reporters.
The 76-year-old remains, unquestionably, the most divisive figure in US politics.
That he stopped short of an outright declaration suggests uncertainty about the impact such an announcement would have on Tuesday's battle for control of Congress.
He said he didn't want to "detract" from the midterms where all 435 seats in the House of Representatives and one-third of the Senate are up for grabs.
But while delighted supporters chanted "four more years" at his Monday evening event, the prospect of his return to the White House could galvanize independent and even some moderate Republicans into voting Democrat.
Trump has endorsed more than 200 Republican candidates running in Tuesday's elections for the Senate, House and state and local posts.
How they fare will be crucial to his fate.
"It is important that some of the candidates he supported win and especially win big," Robert Shapiro, a politics professor at Columbia University, told AFP.
If most triumph then Trump's hold over the Republican Party looks absolute. If they don't, he will likely face a challenge for the Republican nomination.
Florida Governor Ron DeSantis and former Vice-President Mike Pence are tipped as contenders.
"If Trump's candidates lose and especially if they lost badly, that will give other Republican candidates the opening they have been looking for. Watch DeSantis most of all," Shapiro added.
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Republicans are heavily favored to win the House and possibly flip the Senate. If they do take control of both chambers, would they want a president who would likely hijack their agenda?
"The Republicans would want any Republican president, including Trump," said Shapiro.
"It is a fully unified Republican government that can enact conservative policies and make conservative judicial and other government appointments.
"Trump might not be optimal but he would certainly suffice," he added.
Adding further Trump intrigue to Tuesday's ballot are the 27 secretary of state races that are taking place.
Secretaries of state are responsible for validating election results and could be critical at the next presidential election.
In 2020, Georgia's secretary Republican Brad Raffensperger resisted pressure from Trump to overturn his defeat to Joe Biden in the state.
Trump may also see another presidential run as a way of trying to shield himself from the numerous civil, criminal and congressional probes that he is facing.
He is being investigated for his role in last year's US Capitol attack, his efforts to overturn the 2020 presidential election, and the stashing of classified documents at his Mar-a-Lago residence.
In September, New York state's attorney general Letitia James sued Trump and three of his children, accusing them of business fraud.