MIAMI — With the turbulent White House race scrambled in new directions, Donald Trump is campaigning like it all hinges on one all-too-familiar swing state: Florida.

There was late action Wednesday in such unlikely arenas as Arizona and Michigan, too – and in North Carolina, where President Obama tried to energize black support for Hillary Clinton. But Trump marched ahead in his third multi-day visit to the Sunshine State in recent weeks.

The Republican nominee lashed out at “Crooked Hillary” in Miami, predicting that a Clinton victory would trigger an “unprecedented and protracted constitutional crisis” as federal investigators probe the former secretary of state’s email practices.

Conceding nothing in the state, Clinton has also been a frequent visitor. She posed for pictures and shook hands during a surprise visit to a South Florida Caribbean-American neighborhood Wednesday morning.

Both sides agree the New York businessman has virtually no chance to win the presidency without Florida’s trove of 29 electoral votes. Clinton has been ahead there in opinion polls, but Democrats acknowledge that the FBI’s renewed attention to her has helped rally reluctant Republicans behind their nominee. That’s given Trump an enthusiasm boost in Florida and across Midwestern battlegrounds long considered reliably blue territory.

“I’m definitely nervous,” said former Pennsylvania Gov. Ed Rendell, a Democrat. “Democrats in Michigan, Wisconsin and Pennsylvania, if you heard it was over, if you thought those states were in the bag, don’t believe it.”

Perhaps heeding Rendell’s warning, Clinton’s team is devoting new resources to states like Michigan, which hasn’t supported a Republican presidential nominee in nearly three decades.

While she had two appearances Wednesday in Republican-leaning Arizona, Clinton planned to spend part of Friday in Detroit. At the same time, a pro-Clinton super PAC was spending more than $1 million on Michigan airwaves along with at least $1 million more in Colorado, another state where Clinton has enjoyed a significant polling advantage for much of the fall.

Early voting numbers in some states suggest that her challenge stems, at least in part, from underwhelming support from African-American voters. Weak minority support could complicate her path in other states, too, including North Carolina, Pennsylvania and Michigan.

Obama, the nation’s first black president, headlined a rally with singer-songwriter James Taylor in North Carolina on Wednesday, the first of two visits he’s planned this week. Early voting in North Carolina shows a 5 percentage point drop in ballots from black voters from 2012.

“I know there are a lot of people in barber shops, in beauty salons, in the neighborhoods who are saying to themselves, you know, we love Barack, we especially love Michelle, so it was exciting, and now we’re not excited so much,” Obama said on the “Tom Joyner Morning Show.”

“I need everybody to understand that everything we’ve done is dependent on me being able to pass the baton to somebody who believes in the same things I believe in.”

At the same time, Clinton allies are speaking directly to black voters in a new advertising campaign running in Ohio, North Carolina and Florida. The ad from the pro-Clinton Priorities USA shows white Trump supporters screaming at and pushing black protesters, along with Obama warning that voters would lose “everything” if Trump wins.

As the final-days scramble for votes intensifies, Florida remains perhaps the nation’s most critical swing state.

The Trump campaign knows there is no realistic path to the White House without Florida, where polls give Clinton a narrow lead. The New York businessman campaigned in three Florida cities Wednesday – Miami, Orlando and Pensacola – and will follow up with a stop in Jacksonville on Thursday.