Concord, N.C. – North Carolina could be the most important state on the electoral map, with tight races for governor and the U.S. Senate and a seesaw battle for president that could decide the race for the White House.

Republican Donald Trump and Democrat Hillary Clinton have visited North Carolina nearly two dozen times since June, and both were back on Thursday for a pair of stops each in hopes of locking up the state’s 15 electoral votes.

Clinton can afford to lose North Carolina – she retains an edge even with a tightening race – but a defeat here for Trump could close off his path to the White House. Which helps explain why the two ratcheted up their attacks on Thursday, slugging each other in deeply personal terms.

At a partly-filled arena in Concord, a Charlotte suburb, Trump invoked the federal scrutiny of Clinton's private email server, saying a vote for her would create an "unprecedented constitutional crisis" and four years of ongoing investigations.

“She got away with murder. Honestly, she has no right to be running. You know that," said Trump. "It will probably end up, in my opinion, in a criminal trial. Who knows? But it will certainly be spoken of. Americans deserve a government that can work – and really has to work – from day one."

About 200 miles across the state in Greenville, Clinton stumped in Greenville and planned another stop with Vermont Sen. Bernie Sanders and music star Pharell Williams in Raleigh to try to drive millennial voters to the polls.

She said Trump has spent his campaign "offering a dog whistle to his most hateful supporters" and slammed him for getting the endorsement of the Ku Klux Klan's official newspaper, which was deposited on the lawns of a handful of north Georgia Clinton supporters last week.