Donald Trump amplified warnings Monday that Hillary Clinton is “unfit” for office -- and claimed her election would mire the country in a “constitutional crisis” -- as he fought to gain an advantage after the discovery of new emails kick-started the FBI’s dormant Clinton server investigation.

While the impact of the FBI’s announcement isn’t yet apparent in the polls, the Republican presidential nominee has climbed back into contention in Florida and other battleground states.

Two separate polls released Sunday shows Trump in a tight race in Florida, after having chased Clinton’s lead there for essentially the entire election cycle.

The polls, an NBC News/Wall Street Journal/Marist survey and a New York Times/Upshot survey, showed Trump trailing by 1 percentage point and ahead by 4 points, respectively.

However, neither was conducted before the FBI on Friday announced a review of new-found emails possibly connected to Clinton’s use of a private server while secretary of state.

The FBI had investigated the server issue for a year to learn whether Clinton had mishandled classified material. FBI Director James Comey effectively ended the case this summer when he said Clinton was “extremely careless” with regard to classified information but they didn’t have enough evidence to recommend criminal charges.

Trump, who has run a rollercoaster-but-resilient campaign, has taken full advantage of the new email revelations, related to a laptop the FBI has taken in connection with ex-New York Democratic Rep. Anthony Weiner allegedly sexting an underage female. Weiner is the estranged husband of top Clinton aide Huma Abedin.

“Thank you, Huma. Thank you, Anthony,” Trump said at rally Monday in Michigan, while warning that the emails could lead to a criminal trial for a sitting president, if Clinton is elected. He warned this could throw the country into a crisis.

“How can Hillary manage his country if she cannot even manage her emails?” he said.

Still, as Campaign Manager Kellyanne Conway vowed Sunday, Trump has since Friday stayed on message -- weaving his Clinton attacks into his now-familiar campaign speech that promises to create better jobs, to repeal and replace ObamaCare and to “drain the swamp” that is Washington, D.C.

Clinton immediately dived into the new email issue at a rally Monday in battleground Ohio, where Trump has regained a narrow lead since mid-October, when a 2005 audiotape emerged of him boasting about making unwanted advances on women.

“Why in the world would the FBI jump into an election with just eight days to go? There is no case here,” Clinton said at a campaign rally, after apologizing for using the private server and before warning about the dangers of Trump and his “hair trigger” temperament controlling the U.S. nuclear arsenal. 

Aside from the recent polling in Florida, Trump trails the front-running Clinton by just 1 percent point, 46-to-45 percent, in a national ABC/ Washington Post tracking poll.

“We’re doing great in every poll,” Trump also said in Michigan. “We’re winning all over the place.”

The map still favors Clinton, as the candidates battle for the ultimate prize of 270 Electoral College votes on Nov. 8.

But Trump’s uptick in the polls follows his campaign increasing its TV spending.

Trump, in mid-October, for the first time outspent Clinton in TV advertising -- $14.4 million to $13.9 million during the week beginning Oct. 18.

That week, Trump spent $72,134, compared with $65,205 for Clinton. And in Florida, he spent roughly $128,000, compared with $138,000 for Clinton.

Those week-long expenditures compare to Trump previously spending about $3 million a week and Clinton spending about $9.1 million a week since the last primary election, on June 14, according to an analysis published last week by Bloomberg Politics. 

Democratic strategist Ben Tulchin said Monday that Trump’s increased advertising spending is having only a marginal impact -- considering his ability to control the news cycles with raucous rallies, myriad tweets and call-in interviews.

“It’s helped on the margins, to reinforce his messages,” said Tulchin, president of San Francisco-based Tulchin Research. “But it’s really a modest impact because he just dominates the news media. … He’s blunted the impact of paid media.”

Tulchin instead thinks Trump recent, incremental climb is the polls is part of larger patterns occurring throughout the cycle -- Trump making a controversial remark that drops him to about 37 percent in polls, then going back to about 43 when his base returns.

“They so despise Hillary, it makes them run back to Trump,” he said.

The White House will again be decided by a handful of battleground states, remaining extremely close with just eight days left before Election Day.

In other battleground races, Clinton leads by nearly 6 percentage points in Pennsylvania and 3 points in North Carolina, while Trump is ahead by 1.4 percentage points in Iowa, according to the RealClearPolitics poll average.