EXETER, N.H. — Tiny New Hampshire has just four votes in the Electoral College, but Tim Kaine was back here for his third visit in five weeks. At back-to-back campaign appearances, Hillary Clinton’s vice-presidential running mate offered a blunt reason for why.

“This race is close,” the Virginia senator said at a rally Thursday in this picturesque New England town. “I would rather be us right now than them. I think we have a more straightforward path to win and they have a more complicated path. But there is nothing to take for granted because, let’s be honest, it’s been a season of surprises.”

To many Democrats, the biggest surprise is that Donald Trump has mounted a comeback. Despite being battered all summer by his own missteps as well as a barrage of attack ads from Clinton, the Republican nominee has been surging in the battleground states.

Public polls over the past week show Trump leading Clinton in Ohio, Florida and Iowa; moving into a virtual tie with her in Nevada and North Carolina; and cutting into what had been comfortable Clinton leads in New Hampshire as well as Colorado, Michigan, Pennsylvania and Virginia.

Clinton’s return to the campaign trail after her highly publicized bout with pneumonia came at what has turned out to be the low point for her of the general election. She is laboring to regain solid footing before the first of three debates, on Sept. 26.

TRUMP’S ‘BIRTHER’ ADMISSION

Clinton believes Trump has helped her in recent days by reopening painful wounds with a discussion of his long-held “birther” conspiracy. After five years of peddling lies and innuendo about the circumstances of President Obama’s birth, Trump on Friday bowed to the facts and acknowledged for the first time that Obama was born in the United States, though he refused to apologize for his efforts to delegitimize the nation’s first black president.

It is too early to know whether the episode will be a turning point that reverses gains for him in many of the battleground states. Clinton has fundamental advantages in an electoral map that is tilted generally in favor of Democrats because of changing demographics, giving her more mathematical permutations than Trump to win.

State by state, Clinton’s advisers have a sober assessment of where the race now stands. But they believe that, if they can turn out their votes – especially young people, a critical Democratic constituency that has registered soft support for Clinton – they have ample ways to block Trump from winning the necessary 270 electoral votes despite clear deterioration in several states.

“We expected this to tighten. We expect it to tighten even further,” Clinton campaign manager Robby Mook said. “That’s why we built a robust campaign in all 50 states, but especially in the battleground states. It’s going to come down to small margins … .We’re spending a lot of time making sure of our vote.”

CONFIDENCE AMONG REPUBLICANS

For the first time since Trump secured his party’s nomination in May, there is genuine confidence among Republicans that he could win. Trump campaign manager Kellyanne Conway said “we own both the momentum and enthusiasm dynamics right now.”

“Everybody loves a winner, so people now see these polls tightening where we’re up, tied or within the margin of error in nearly all of the swing states,” Conway said. “People are starting to see that Trump can actually pull this off.”

Strategists for Clinton and her top allied super PAC, Priorities USA, are intently analyzing the polling shift to understand the forces propelling Trump.

Nowhere have Trump’s gains been more consistent than in Ohio, a swing state that President Obama carried twice and where the Clinton campaign has been vastly out-working Trump’s on the ground and out-spending it on the airwaves. In the Real Clear Politics average of recent Ohio polls, Trump leads Clinton 42.5 percent to 40.8 percent in match-ups that include both third-party nominees, Gary Johnson of the Libertarian Party and Jill Stein of the Green Party.

Geoff Garin, the Priorities USA pollster, said Trump’s surge in Ohio and elsewhere is largely due to his consolidation of Republican and Republican-leaning independent voters. He said that at the moment at least, these voters – the Mitt Romney coalition in 2012 – see Trump as an acceptable alternative to Clinton following several weeks of relatively disciplined campaigning by Trump.

“The phenomenon we are seeing right now primarily is just Donald Trump being normalized among Republican voters,” Garin said.