Donald Trump, Richard Burr, Pat McCrory in peril as Republicans fight to keep North Carolina

GRAHAM, N.C. — Spread out like a Burma-Shave ad, the message on a trio of roadside signs was jarring but familiar: Lock. Her. Up.

Auto body owner Danny Hulon said he can’t stand the idea of Democratic nominee Hillary Clinton moving back into the White House, so he stuck the little signs along North Carolina Highway 87 to echo the mantra of Republicans who say the former secretary of state should be punished for her unauthorized use of private email and wobbly response to the attack on Benghazi, Libya, during President Obama’s first term.

Mrs. Clinton is ahead of Republican rival Donald Trump by the low single digits in North Carolina, according to the latest polls, yet folks like Mr. Hulon say the battle for his swing state will go down to the wire, even if he isn’t impressed by Mr. Trump’s overall strategy.

“He’s fighting too many people,” he said Friday, as Mr. Trump held rallies in Greensboro and Charlotte.

A short drive away, the Chatham County Democrats plotted to turn doubts about Mr. Trump into wins for Mrs. Clinton and a slew of down-ballot candidates, stuffing 7,500 mailers with “blue ballots” that highlight this year’s Democratic options.

North Carolina is in play, and it’s about much more than the presidential race.

Senate Republicans clinging to a 54-46 majority face an unexpected headache in the Tarheel State, where two-term incumbent Sen. Richard Burr is at risk of losing his seat to his Democratic challenger, Deborah K. Ross, a former state lawmaker.

If that weren’t enough, Gov. Pat McCrory, a Republican, faces an uphill re-election battle against Attorney General Roy Cooper, a Democrat, amid a high-profile feud over a transgender bathroom law that prompted economy boosters such as PayPal and the NCAA to retreat from the state.

“I find it exhausting, for the volunteers,” said Joanne Wittenborn, former president of the Greater Greensboro Republican Women’s Club. “But it’s exciting, and it has rallied everybody, and we’re all hands on deck.”

The intensity of the campaign took an ugly turn over the weekend when someone firebombed the Orange County Republican Party headquarters in Hillsborough and scrawled graffiti denouncing “Nazi Republicans.”

Both Mr. Trump and Mrs. Clinton condemned the attack.

In the Raleigh-Durham area, normal television ads hardly seem to exist. They are crowded out by a steady roulette of 30-second spots about Mr. Burr’s performance in Washington, the danger of men using the ladies’ room and Mr. Cooper’s boasts that as attorney general he cleared a backlog of untested rape kits.

Mr. Trump even shifted volunteers from Virginia, which has swung heavily toward Mrs. Clinton, into North Carolina, hoping to keep the rest of the South in Republican hands.

President Obama won North Carolina in 2008, ending a Republican winning streak that stretched back to Jimmy Carter’s election in 1976, only to cede the state back to Mitt Romney four years later.

But Randy Voller, a former chairman of the North Carolina Democratic Party, said there seemed to be more enthusiasm for Mr. Romney than there is for Mr. Trump, particularly among Republican operatives who supported primary challengers such as Sen. Ted Cruz of Texas.

“I don’t see that same level of, like, ’joyful warrior,’” he said.

Mr. McCrory, meanwhile, faces headwinds for signing the law known as “HB2,” which requires people to use public bathrooms that correspond with the biological sex on their birth certificates.

State lawmakers passed the law in response to a Charlotte ordinance that extended certain anti-discrimination protections to the LGBT community.

Opponents of the ordinance said it would essentially create safe zones for peeping Toms in women’s bathrooms, yet the Republican push to overturn the city’s decision resulted in a backlash from entities that viewed HB2 as a codification of anti-LGBT discrimination.

“Our governor has taken the state back 100 years,” said David Spear of Madison, who stood among protesters a few blocks from a Trump rally in Greensboro.

As companies or athletic competitions pull out of the state, the controversy threatens to distract from the focal point of Mr. McCrory’s campaign — his stewardship of a “Carolina comeback” that has added nearly 300,000 jobs and slashed the unemployment rate since he took office in 2013.

“He’s turned the state around, he’s turned the economy around. Things are working again in North Carolina,” said Lee Green, chairwoman of the N.C. GOP District/County Chair Association.

Yet Steven Greene, a politics professor at North Carolina State University, said the die may already be cast.

Mr. McCrory ran as a center-right, pro-business Republican in 2012 and picked up some Democrats and left-leaning independents, he noted, yet those same voters are linking the governor to this year’s “culture wars.”

“McCrory has become the face of HB2 for better or for worse, and I think most polling indicates that it’s for worse,” the professor said.

The issue has spread to the state’s competitive race for U.S. Senate.

In their only televised debate, Ms. Ross called the state law discriminatory. Mr. Burr also said the law should be reversed, but only if Charlotte revisits its ordinance with greater input from the public.

Mr. Burr, a former House member and two-term Senate incumbent, is clinging to a lead in the low single digits, according to polls, as he fends off Ms. Ross’ assertions that he hasn’t achieved much for North Carolina during his two decades in Washington.

Mr. Burr’s supporters say he has achieved plenty, including the ABLE Act, which helps families who have children with disabilities pay for lifelong expenses through tax-advantaged savings accounts.

“He doesn’t gallivant to the media,” said Tom Shumaker, who was among state Republicans waving pro-Burr signs to passing motorists in Research Triangle Park ahead of the Thursday night debate.

The Burr campaign has portrayed Ms. Ross as soft on crime, citing her record with the American Civil Liberties Union, and pointed to her support for Obamacare — she said it is “better than what we had” — despite an exodus of companies from North Carolina’s insurance exchange.

Ms. Ross has been able to draw outside money from national Democrats and super PACs, keeping the race close, yet some analysts say Mr. Burr is in better shape than Mr. McCrory or Mr. Trump.

“I think the biggest threat for [Mr. Burr] is reduced Republican turnout because voters are so demoralized by Trump and because the Republican ground game in North Carolina is much weaker than usual,” said Jason M. Roberts, a politics professor at the University of North Carolina, Chapel Hill.