Republican presidential nominee Donald Trump campaigned at The Venetian in Las Vegas on Sunday. There, rally-goers were enthusiastic about FBI Director James B. Comey’s decision to renew an investigation into Democratic presidential nominee Hillary Clinton’s email server. (Zoeann Murphy/The Washington Post)

Republican presidential nominee Donald Trump is redirecting his attention to traditionally Democratic states in the final days of the 2016 campaign in an urgent attempt to expand what for weeks has been an increasingly narrow path to victory.

Following FBI Director James B. Comey’s surprise announcement Friday that the agency would once again examine emails related to Hillary Clinton’s time as secretary of state, Trump and his advisers see a fresh opportunity to make gains in states that most public polls have shown as out of reach. They spent the weekend deliberating ways to seize on what they see as a dramatic turn in the campaign’s closing chapter and scramble the political map following a rough stretch beset by controversy.

Trump held rallies Sunday in Colorado and New Mexico, and he was scheduled to make two stops Monday in Michigan — and visit Wisconsin the day after that.

Clinton, meanwhile, is focused on shoring up turnout and enthusiasm, particularly among minority voters, in such critical battlegrounds as North Carolina, Florida and Ohio. Early voting data from Ohio contains ominous signs of a lack of enthusiasm for Clinton, notably in places such as Cleveland’s Cuyahoga County, where high black turnout propelled President Obama to victory in 2008 and 2012.

Latest results from the Post-ABC presidential tracking poll

As a result, Clinton’s campaign has launched an intensive effort to send her most popular surrogates, including the president, first lady Michelle Obama and rapper Jay Z, across the country.

Clinton’s operation has also come out forcefully against what aides described as Comey’s “unprecedented” decision to release a “vague” and “misleading” letter. One senior aide said the campaign does not believe Comey’s actions have measurably changed the state of the race.

Trump’s sudden blue-state push faces steep challenges both organizationally and demographically. In several of the states in question, millions of early votes have already been cast, and polling indicates that the planned shift faces hurdles.

Nationally, the contest is tightening in tracking surveys to within the margin of error, but Trump remains behind by mid-to-high single digits — much as Mitt Romney was four years ago — in the states he is hoping to turn into unusual final-week fronts.

According to the latest Washington Post-ABC poll, a majority of all likely voters is unmoved by Comey’s decision, which has spurred a fierce backlash from Clinton backers.

Choose your own electoral adventure: Map out the ways Clinton or Trump could win

Trump campaign chief executive Stephen K. Bannon has settled on three states in particular — Michigan, Wisconsin and New Mexico — where the candidate and campaign will devote more time and money, said four people familiar with the discussions who spoke on the condition of anonymity to discuss internal campaign talks. All three states were won by Obama in 2008 and 2012.

Bannon believes that if GOP voters rapidly “come home” nationally in light of recent events, that turnout plus late-breaking support among independents and blue-collar workers could bring new states into play beyond Pennsylvania, Nevada and Colorado — Democratic strongholds where Trump has been campaigning for months and remains behind, the people said.

Democrats and many Republicans remain skeptical that Trump can reach 270 electoral votes with this 11th-hour ploy or any other. But Trump strategists argued Sunday that the race’s fast-changing dynamics and unpredictability give them an opening despite polling and fundamentals leaning in Clinton’s favor.

These advisers privately described Trump’s path to the White House not as a direct shot but as a series of razor-thin upsets in several much-discussed battlegrounds, as well as unexpected bank shots in blue states. All of it would depend on better-than-
expected Republican support nationally, they said.

“States that haven’t usually been open to Republican nominees are going to see Mr. Trump and his supporters again and again,” David Bossie, Trump’s deputy campaign manager, said in an interview. “We see this like 1980 and 1984, when union leadership was against Ronald Reagan but many union members went for him. That’s what we think can happen in the Upper Midwest and in states like New Mexico — blue-collar voters going for Donald Trump.”

Bossie said Clinton should expect a “full-frontal assault” before Election Day. “We’re on the offensive everywhere.”

Bossie said that Comey’s letter to congressional leaders about renewing the Clinton probe was not the impetus for the expansion. He said Trump’s trips to Michigan, Wisconsin and New Mexico, as well as Maine, New Hampshire and Pennsylvania, were planned before the FBI director made his announcement and were based on confidence in Trump’s appeal to non-Republican voters.

For Clinton, her campaign’s concentration has been on stoking its support in places where Democrats are assured about their campaign infrastructure but concerned that some Democratic voters, particularly minorities, may choose to stay home.

As Trump makes moves into Michigan and Wisconsin, the Clinton campaign and its allies are dubious about whether the Trump campaign will actually be able to move numbers there or ramp up their organization. But they are trying to energize voters in cities, including Detroit and Milwaukee, where her success could depend on a robust urban turnout should Trump attract unexpected working-class support.

The Clinton campaign also recently began spending money on television in Wisconsin for the first time this year, casting the ad buy as a way of bolstering support in a state with a hard-fought Senate race.

Michigan, which Democrats have carried in presidential races since 1992, is a clear test of the strength of Democrats’ blue wall. Much of Obama’s margin came from exceptional turnout in Detroit’s Wayne County; he won it by 382,032 votes, on the strength of black and Muslim turnout that Democrats acknowledge this year is not yet at its Obama-era pace.

Clinton supporters learned nervousness in Michigan in this year’s Democratic primary, when public polls failed to catch a surge by Sen. Bernie Sanders (I-Vt.). Some white pockets of the Detroit area that went to sleep on the Michigan-born Romney are visibly more active for Trump.

On Sunday at a rally in Taylor, a Detroit suburb, Clinton’s running mate, Sen. Tim Kaine of Virginia, suggested that the bombshell nature of Comey’s letter would end up helping Democratic turnout.

“It’s kind of revved up some enthusiasm, a little bit of righteous anger,” Kaine said.

Clinton is also still attempting to expand her own map, making a serious play to flip Arizona, a state the campaign believes she can win.

One Democratic strategist outside of the campaign said that private polling data had begun to show a closer race before Comey’s letter, due largely to Republican voters drifting back into Trump’s fold.

With early voting already underway in most of the contested battlegrounds, Clinton has dispatched an army of surrogates to get out the vote, including celebrity artists Jay Z, Jennifer Lopez and Katy Perry. On Tuesday, the president will rally in Columbus, Ohio, and on Wednesday he will appear in Raleigh, N.C. Stops in Jacksonville, a city where African Americans make up 30 percent of the population, and South Florida, are planned, as are more events headlined by Michelle Obama.

In Nevada, Florida and Colorado — states Obama won — early and absentee turnout has been strong overall and is so far on track to match or exceed 2012 levels, according to available data.

But in Iowa and Ohio, turnout levels have been low. Take Cuyahoga County in Ohio, a Democratic stronghold, where in-person and absentee voting is down by more than 50 percent, compared with a similar period in 2012. That is in part because of the state’s cutback in early voting days, but it does not bode well for Democrats’ efforts to capitalize on their historic strength with the early vote.

Disproportionately high black turnout in Cuyahoga and Franklin counties were important factors in helping Obama eke out a two-point win in that state over Mitt Romney in 2012, said Cornell Belcher, one of Obama’s pollsters in 2008 and 2012.

“You don’t see the sort of energy there this time around as you saw before,” Belcher said. “If on Election Day our electorate is 74 percent white, Hillary Clinton is probably not going to be president.”

In North Carolina, another battle­ground that Trump almost certainly must win to take the White House, Democratic turnout has fallen compared with 2012 in early voting — although Democrats continue to maintain a significant lead over Republicans. Black turnout has also come up short.

Clinton senior adviser Joel Benenson struck an optimistic note over the weekend, noting that black turnout in early voting on Saturday in pivotal counties in both Ohio and North Carolina exceeded 2012 levels, which he cast as a microcosm of enthusiasm and engagement among that group.

“For voters of color, this is the first time in their life that they’re hearing from a presidential candidate the kind of racially divisive rhetoric they’ve heard from Donald Trump in this campaign,” Benenson said. “That is going to be on the minds of every voter on Election Day.”

Democrats also say they expect a high number of crossover voters because of Trump’s struggles with more centrist Republican voters and how Clinton is overperforming Obama with college-educated white voters. That could mean that while Republican ballots are coming in at a respectable clip, Trump may not be able to rely on all of those voters.

In coming days, Trump allies will attempt to counter the Clinton campaign’s barrage of surrogates with Trump family members and high-profile supporters, including former New York mayor Rudolph W. Giuliani, who will appear this week in historically Democratic enclaves and suburban swing districts. The campaign announced Sunday that Trump’s wife, Melania, will speak Thursday in the moderate suburbs of Philadelphia.

Most Democrats are buoyed if somewhat skittish about the polls. In the Post-ABC poll, 6 in 10 voters say the Comey news will make no difference in their vote, while just over 3 in 10 say it makes them less likely to support her. Two percent say they are more likely to back her as a result.

In the three new states that Trump is targeting, he is trailing. In Michigan, he is behind by an average of eight percentage points, a margin nearly identical to Obama’s nine-point margin there in 2012. He is behind by an average of six points in Wisconsin, also similar to Obama’s margin in 2012. New Mexico’s polling average shows Trump behind by 10 percentage points, although there have been few regular state-level surveys, and Trump’s advisers said their internal polls show a closer race. In Pennsylvania, Clinton leads by an average of six points in recent polls.

Trump bragged about his new strength in recent polls Sunday morning, despite repeatedly claiming that polls were “rigged” against him on the campaign trail. The celebrity businessman also claimed, without evidence, that “Twitter, Google and Facebook are burying the FBI criminal investigation of Clinton.”

“We are now leading in many polls, and many of these were taken before the criminal investigation announcement on Friday — great in states!” Trump tweeted Sunday.

Clinton urged churchgoers in Florida on Sunday not to be “distracted by all the noise in the political environment.”

During her remarks to about 300 people at the New Mount Olive Baptist Church in Fort Lauderdale, one of several planned stops for the day in the Miami area, Clinton made no mention of the renewed FBI scrutiny related to the private email server she used as secretary of state. But she stressed the value of perseverance when confronting obstacles in life.

“Everyone — everyone — is knocked down in life,” Clinton told the predominantly black congregation. “And as my mother showed me and taught me, what matters is whether you get back up. And those of us who are people of faith know that getting back up is what we are called to do.”

Comey reignited a political firestorm over the emails when he alerted select members of Congress on Friday that FBI officials had detected a batch of emails pertinent to the case during an “unrelated” investigation. Persons close to the situation have told The Post that the emails were found on a computer belonging to former congressman Anthony Weiner (D-N.Y.), who is under investigation for allegedly exchanging lewd messages with a 15-year-old girl. Weiner is the estranged husband of top Clinton adviser Huma Abedin.

Scott Clement and Jose A. DelReal in Washington, John Wagner in Fort Lauderdale, Fla., Sean Sullivan in Las Vegas, David Weigel in Detroit and Vanessa Williams in Greensboro, N.C., contributed to this report.