Donald Trump's path to the White House has gained growing plausibility with a flurry of poll numbers showing the Republican nominee on the ascent over Hillary Clinton in some of the most crucial battleground states.

Trump's new momentum is the product of a hazardous period for Clinton, in which she earned fervent backlash for deriding half of his supporters as belonging in a "basket of deplorables" and then nearly collapsed in public while fighting a previously undisclosed bout with pneumonia that renewed lingering questions about her health and took her off the campaign trail for most of this week.

Three polls showing Trump inching ahead in Ohio, survey results placing him in the lead in Florida and still another poll giving him a slim advantage in Nevada have jolted hardened perceptions about the race 11 days before the first debate in Hempstead, New York. Additionally, a CBS News/New York Times survey of the contest released Thursday found the candidates statistically even nationally, knotted at 42 percent apiece.

Many political observers who concluded the race was slipping out of Trump's reach after his disastrous August are now recalibrating their opinions and wondering how Clinton will stop her own September slide – a stark indication of how volatile the campaign remains with more than seven weeks until Election Day.

"Hillary's just not a very good candidate. She doesn't have campaign skills, comes off as shrill, and has a cloud hanging over her," says Scott Reed, the senior political strategist at the U.S. Chamber of Commerce. Trump has "shown a new level of message discipline. That's why this election has tightened up."

Polling out of Ohio – where surveys are now tracking Trump ahead by 3 to 5 percentage points – set off alarm bells within the Clinton campaign, which suddenly announced it was dispatching Sen. Elizabeth Warren of Massachusetts and Clinton's former rival, Sen. Bernie Sanders of Vermont, to the Buckeye State this weekend to pitch the former secretary of state to young voters uninspired by her candidacy. Warren and Sanders will promote Clinton's plan to make college debt-free across five cities on Saturday.

"We always expected the race to tighten up," Clinton campaign chairman John Podesta said on a conference call Thursday. "They call these 'battleground states' for a reason. They are going to be hard-fought."

A Bloomberg survey of Ohio found that a higher proportion of men and older voters are indicating their likelihood to cast ballots – a glaring sign that Clinton needs to rally younger voters and minorities in order to offset that surge benefiting Trump, whose victory is predicated on garnering an unprecedented portion of the white vote.

Liberal advocates also are openly expressing worry that millennials ages 18 to 34 – 45 percent of which are minorities – don't recall or care that the last sustained era of economic prosperity occurred under President Bill Clinton.

"My concern is that they're not turned on to participate," Maria Teresa Kumar, president of Voto Latino, said at a Brookings Institution event in Washington on Wednesday.

Facing little room for error, Trump's climb remains uphill, but Republican strategists are beginning to see an emerging electoral map that would allow him to squeak out a victory.

Trump must hold all 24 states carried by Mitt Romney in 2012 and add Ohio and Florida to the tally. A loss in Florida, Ohio or in increasingly competitive North Carolina – which Romney carried by just 2.2 percentage points over President Barack Obama – would hand Clinton the presidency.

Virginia, the fourth-most competitive state in 2012, has drifted into Clinton's column, analysts believe.

"Virginia's over. He can't win Virginia," former White House press secretary Ari Fleischer says.

Though polling has shown Trump closing the gap in the commonwealth, the demographics of northern Virginia – which holds a substantial population of moderate, college-educated women and a plethora of minority groups – don't bode well for the New York City billionaire's strident, nationalist messaging.

Still, he has a path without its 13 electoral votes – though it's a narrow one for sure.

Pennsylvania remains a key target for Trump. The top super PAC supporting his candidacy, Rebuilding America Now, has launched a two-week, $1.3 million television advertising flight that never flashes Trump on the screen in every Keystone State market outside of Philadelphia. But no Republican presidential contender has captured Pennsylvania in close to three decades and Clinton still holds a solid single-digit advantage there, powered by her strength across the Philadelphia suburbs.

Assuming a loss in Pennsylvania means Trump will have to run the table and flip three battlegrounds that Democrats have carried the last two cycles: Colorado, Iowa and Nevada.

This thin lane may offer his most realistic chance.

Trump has a sturdy organizational front in Iowa, led by the son of Gov. Terry Branstad, and the state's base of white, working-class evangelicals has given Trump a leg up. But he's also drawn Clinton essentially to a tie with college graduates there, a rare case where he's made inroads among one of her strongest voting blocs. The latest poll placed him up in Iowa by 8 percentage points.

Meanwhile, a Monmouth University survey of Nevada released Wednesday found Trump pulling narrowly ahead of Clinton, based on a swing of independents toward the Republican.

"The race in Nevada is still tight, but the momentum has swung toward Trump," said Patrick Murray, director of the Monmouth University Polling Institute.

Carrying Iowa and Nevada would place Trump at 265 electoral votes to Clinton's 264.

In this scenario, it would all come down to Colorado – a state that remains structurally inclined toward Clinton but where Trump is showing some initial signs of a comeback.

An Emerson College poll out Thursday showed Trump overtaking Clinton 42 percent to 38 percent – a lead just outside the margin of error – after other polls this summer showed Clinton ahead by double digits.

If Trump upsets Clinton in Colorado, it puts him at 274 electoral votes to her 264. (A candidate needs 270 electoral votes to clinch the presidency.)

But if he drops any of the three – Iowa, Nevada or Colorado – he's doomed.

On the other hand, a surprise Trump victory to net Pennsylvania's 20 electoral votes would negate the need for wins in the trio. That would get Trump to 273 electoral votes.

If some states come down to margins of 2 to 3 percentage points, the strength of an individual campaign's get-out-the-vote efforts could prove to be the deciding factor. And the Republican National Committee, in conjunction with the Trump campaign, is boasting a ground effort it claims is ahead of the Clinton camp's in terms of organizers and volunteers.

When including youth volunteers, the RNC counts having 5,500 organizers in 225 cities that have knocked on 2 million doors since August. The party has registered 730,000 new Republicans during the 2016 cycle, providing them with a reported net gain of more than 200,000 new voters over the Democrats.

The Clinton campaign has made much of its advantage in the number of physical offices it's opened, but Sean Spicer, the RNC's chief strategist, has mocked that metric.