A month ago, the perennial swing state of Ohio was slipping away from Hillary Clinton, who was struggling to win over working class whites and impress jaded millennials.

Today, Ohio looks more and more like it is hers to lose.

The story of why is about Donald Trump: The Republican nominee delivered a woeful opening debate performance, spent days feuding with a former Miss Universe, and it was all capped off the following week by news of an explosive 2005 tape showing Trump seemingly bragging about sexual assaulting women.

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The Clinton campaign stresses that it never abandoned Ohio, even as polls showed the state tilting away from her several weeks ago, with some showing Clinton losing to Trump by as many as 5 points – a far cry from the narrow win President Obama delivered against Mitt Romney. Trump’s appeal among working class white voters – especially white men – sliced into Clinton’s support among traditional Democrats.

But even as their candidate focused her appearances on other battleground states, the Clinton campaign continued to push their economic message and register voters – especially minorities and young people – with a ground game far superior to that of the Republicans.

Trump’s stumbles on the national stage, Ohio observers say, have hurt him with moderate Republicans and independents – voters who may never have been solidly for him but had hesitations about Clinton. That’s left the Clinton organization on firm footing heading into the final month of the race, with early voting set to start on Wednesday. According to the latest CBS News poll, Clinton leads Trump among likely voters in Ohio by four points, 46 percent to 42 percent.

Along with the lewd videotape that landed last Friday, The New York Times revealed that Trump may have not paid any federal income taxes for nearly two decades. And Newsweek discovered that the most recent Trump construction projects purchased steel and aluminum from manufacturers in China rather than from corporations based in the U.S.

In Ohio, where layoffs in the steel industry have hit hard over the last two decades, Clinton seized on the opening.

“He claims to be on the side of workers,” Clinton said of Trump on Monday at a rally in Columbus. “He especially likes to talk about how he supports America steel workers. He even had the nerve, this is what kills me, he even had the nerve about how American steel will send skyscrapers soaring. The whole time he was hiding the truth, hiding the fact that he choose to buy illegally dumped Chinese steel instead of American steel.”

It was a version of a refrain she delivered on Sunday during the second presidential debate in St. Louis. And earlier in the week, she took to Toledo and Akron to lay out her economic plan.

A few days later, husband Bill Clinton was dispatched to tour the Rust Belt by bus. Other surrogates have peppered the state as well. This past weekend, as Trump struggled to keep the GOP from abandoning him, thousands of Democratic volunteers fanned throughout the state in a final push to register voters before the Tuesday deadline.

Perhaps the most effective surrogate of all will kick off the start of Ohio’s early voting period at the end of the week: Obama will headline a dinner here on Thursday and a rally on Friday.

Her aides don’t see Ohio as a must win – Robby Mook released a memo to supporters obtained by CBS News last month listing Clinton’s “many paths to 270 electoral votes,” some of which did not include the Buckeye battleground.

“Put a different way, of these battleground states, Hillary can win just one (Florida, Ohio, or North Carolina) and win the presidency, which means the six additional states would only add more electoral votes to her total,” Mook wrote in the memo.

But it is a must win for Trump, and with the dramatic shift in public opinion, it’s now a battleground where they believe he can be stopped.

“Before this latest downward spiral bombshell over the weekend, Trump support among our membership was eroding pretty steadily,” Michael Gillis, the Ohio communications director for the AFL-CIO, told CBS News, disputing the notion that the Clinton campaign had given up on the state and attributing it to a scheduling lull.

According to the AFL-CIO’s internal polling, Trump’s union support had dropped 12 points since June, which Democrats in the state credit to an increased awareness of Trump’s fraudulent business record.

“At the very end of September, we had him at 32 and Clinton at 52 – that’s a 20 point spread. It’s the largest in our battleground states with the exception of Wisconsin,” Gillis said.

Last week, the Ohio AFL-CIO distributed 125,000 mailers titled “Trump Stiffs American Steelworkers,” citing articles that Trump had profited from low Chinese pricing instead of buying American steel. Leaflets distributed at the office say the same.

It’s a message that popular Ohio Democrats like Senator Sherrod Brown and Congressman Tim Ryan also sunk their teeth into as they waded through one-time Democratic bastions along Ohio’s eastern border during a bust tour with Bill Clinton.

“Donald Trump, all he does is run his mouth and pad his pockets,” Brown told a riled up crowd last week at a Union Hall in Canton after blasting Trump for buying Chinese steel.

Ryan’s introduction of Clinton was even more intense. “He will gut you and he will walk over your cold dead body and he won’t even flinch,” he said of Trump at a pancake breakfast in Youngstown.

Clinton matched their insults with his wife’s plan to invest in American manufacturing and infrastructure, grow labor unions, and raise wages, a message that finally seems to be taking hold in Northeast Ohio, where Trump has tried to run up the score with the white working class.

“Bill Clinton seems like a pretty decent messenger for that demographic — Ohio is whiter than the nation and it’s white population is less educated than the nation,” Kyle Kondik, the managing editor of Sabato’s Crystal Ball, told CBS News. “And if Trump over performs with that demographic, it’s a problem. So I do think it’s smart for her to limit the losses amongst that group because that’s almost half the voters in Ohio.”

At a debate watch party in Hamilton County on Sunday night, Trump supporters were indifferent to the wreckage their candidate has racked up over the past month. A suburban woman in an InfoWars t-shirt clapped incessantly for 90 minutes, and the rest of the crowd cheered for Trump after every exchange. CBS informally polled the crowd at the end of the night, and overwhelmingly they agreed Trump had won the debate handily.

“That’s the thing, he’s only appealing to the people who already support him,” Michael Hartley, who heads a public affairs and political consulting firm in Columbus, told CBS News.

One Republican strategist familiar with polling in Congressional districts in Ohio pinned the start of Trump’s decline to his first debate performance. An all-time record number of viewers tuned in, and after it was over many were disappointed by Trump and had a more favorable view of Clinton. When he polled a congressional district in Ohio the following day, Trump went from being up by 6 to up by 2.

This same strategist also believes that the Trump campaign’s lack of a ground game is starting to wear thin.

“Folks working on Trump’s Ohio campaign – God bless them, they are doing a fantastic job,” he said. “But, it comes from the top: there is no investment in it. It’s, ‘Hey, we’re going to depend on yard signs and rallies.’ That’s how they see getting out the vote, that’s how they see ground game. That may work in some other states that are not Ohio. But here, you got to go get your voters.”