Donald Trump in Toledo, Ohio. Credit:AP Clinton, campaigning in North Carolina, sought to borrow from first lady Michelle Obama's star power as her campaign warned supporters that the presidential election is likely to be closer than polls now appear. "As Michelle reminds us, this election is about our kids and, in my case, our grandkids," Clinton said. "We have a job to do. Starting right now, let's come together. Let's work together and be hopeful and optimistic and unified." Obama called Clinton a friend, and praised her qualifications and determination. "Hillary doesn't play," Obama said to laughter. Campaigning earlier Thursday in Springfield, Ohio, Trump claimed again that Clinton appeared "tired" after the last two debates. He seemed to imply that she was on the verge of needing physical assistance.

Trump said, is "a low energy person." Then, without presenting any evidence, he claimed that she was in bad physical shape after their most recent debates. "I watched after the last debate and after the second debate. She was tired, wow. She walked off that stage, of course she had a lot of people around; they had a lot of people around her, which was smart," Trump said. No evidence has emerged that Clinton was suffering physically during or after the debates. Trump has regularly sought to raise doubts about Clinton's health. He recently began airing a television ad that shows Clinton stumbling as she tried to get into a vehicle after a ceremony commemorating the September 11, 2001, attacks in New York. After that incident Clinton revealed that she had been stricken with pneumonia. Trump also took aim at the Clintons' charitable foundation and financial dealings, pointing to private communications released by the anti-secrecy group WikiLeaks, including a memo by top Bill Clinton aide Doug Band.

"The more emails WikiLeaks releases, the more lines between the Clinton Foundation, the secretary of state's office and the Clintons' personal finances, they all get blurred," Trump said. Band's memo detailed what he called "Clinton Inc.," a web of lucrative business ventures and overlapping charitable work. The memo was discovered in hacked emails from John Podesta, who is now chairman of Hillary Clinton's campaign. In an interview published Thursday by Billboard magazine, Bill Clinton weighed in on Trump's criticisms, saying that the attacks on his foundation are frustrating. "It's hard to hear because I know good and well that a lot of the people that are saying it know it's not true. It's an insult to all the people who have worked there," he said in an otherwise favourable profile of the former president's charity and its ties to top performing artists, including Jon Bon Jovi. His running mate, Indiana Governor Mike Pence, visited Omaha and western Iowa, while Senator Tim Kaine, the Democratic vice presidential candidate, was also campaigning in Ohio.

Kaine told supporters in Lorain, Ohio, that the state could seal the election for Clinton. "You guys are more than a battleground. You are a checkmate state," Kaine said. "If you win it, you done won it. If we win Ohio, the race is over." Polling released Thursday afternoon by Quinnipiac University showed the tick-tock nature of the race in the closing days. According to the poll, Trump holds a one-point edge over Clinton in Georgia - 44 percent to 43 percent - but they're tied at 44 per cent each in Iowa. In North Carolina, Clinton holds a four-point advantage (47 percent to 43 percent), while she holds a 12-point edge in Virginia. Clinton tops Trump 48 per cent to 42 per cent among likely voters in the tracking poll conducted jointly by The Washington Post and ABC News. Clinton's margin in the survey has barely changed from her 47-43 edge in a mid-October Post-ABC poll, but is less than the double-digit leads in earlier waves of the tracking survey reported by ABC News through Monday. More than three in four Clinton and Trump supporters say they are "very anxious" at the thought of the other candidate becoming president, fears that underscore perceptions of the election's high stakes and the distinct contrast between contenders.

In recent days Clinton has also been warning supporters not to assume that because she holds a lead in national polls that their votes are unnecessary. Her campaign released an online video Thursday in which campaign manager Robby Mook inveighs against complacency. "Donald Trump has been going around telling people not to listen to the polls and saying that he can still win this race," Mook says. "Well, you know what? He's absolutely right." "We call states like Florida, North Carolina and New Hampshire battlegrounds for a reason." he added, "They can go either way." In a sign of how competitive the race remains in Florida, Clinton is scheduled to campaign Saturday night in Miami alongside the singer Jennifer Lopez. The Washington Post