WASHINGTON -- Polls show the presumptive presidential nominees, Democrat Hillary Clinton and Republican Donald Trump, in a close race for the White House in November.

While the surveys indicate that both candidates are unpopular with the electorate, someone is going to win this fall. Here are three ways it could be Trump.

1. His opposition to free trade resonates with Democratic voters.

Trump has blamed free-trade agreements for the hemorrhaging of U.S. jobs as factories move overseas. It's the same argument that U.S. Sen. Bernie Sanders of Vermont has made during his campaign.

"The terrible trade deals that Bernie was so vehemently against and he's right on that will be taken care of far better than anyone ever thought possible and that's what I do," Trump said June 7 after winning the New Jersey primary.

Campaigning in Indiana before his victory there May 3 clinched his nomination, Trump criticized United Technologies Corp. for moving hundreds of jobs in its Carrier unit to Mexico from Indianapolis.

"You're looking at a situation in our country where our jobs are being ripped out of our states," he said.

Remember Sanders' upset victory in Michigan? According to according to network exit polls reported by CNN, 56 percent of Democratic primary voters said trade with other countries takes away American jobs, and 57 percent of them supported Sanders.

Just as Ronald Reagan lured socially conservative, ethnic voters to cross party lines and become what would be known as Reagan Democrats, Trump is eyeing traditionally Democratic households in states like Ohio (where no Republican ever has been elected president without carrying), Michigan, Pennsylvania and Wisconsin.

2. Some Sanders supporters would rather vote for anyone but Clinton.

Bernie Sanders must really dislike Crooked Hillary after the way she played him. Many of his supporters, because of trade, will come to me. — Donald J. Trump (@realDonaldTrump) June 9, 2016

Bernie Sanders was right when he said that Crooked Hillary Clinton was not qualified to be president because she suffers from BAD judgement! — Donald J. Trump (@realDonaldTrump) June 2, 2016

Bernie Sanders is being treated very badly by the Dems. The system is rigged against him. He should run as an independent! Run Bernie, run. — Donald J. Trump (@realDonaldTrump) May 16, 2016

Trump has reached out to Sanders supporters, hoping that their distaste over their candidate's defeat overcomes the fact that Sanders and Clinton agree on most issues.

"To all of those Bernie Sanders voters who have been left out in the cold by a rigged system of super-delegates, we welcome you with open arms," Trump said after the New Jersey primary.

3. Voter identification laws keep Democrats from the polls.

Especially after the five Republican-appointed U.S. Supreme Court justices eviscerated the Voting Rights Act in 2013, GOP-controlled legislatures have moved to enact legislation requiring specific forms of identification before residents can vote.

New voter-ID laws will be in place in 17 states in time for the presidential election, including battlegrounds Ohio, North Carolina and Virginia, according to the Brennan Center for Justice at New York University School of Law.

Supporters said the laws are needed to combat voter fraud. But President George W. Bush's administration spent five years looking for people impersonating other voters, the type of fraud addressed by such laws, and failed to secure a single conviction, according to the Brennan Center.

The current Pennsylvania House speaker, Mike Turzai, a Republican, acknowledged in 2012 that the state's ID law would "allow" GOP nominee Mitt Romney to carry the commonwealth. That statute was thrown out by a state judge who said the measure would deprive Pennsylvanians of their "fundamental right to vote" and there was no evidence of voter fraud.

The U.S. Justice Department called such laws discriminatory. A Brennan Center study said 25 percent of voting-age blacks and 16 percent of voting-age Hispanics lacked the identification these laws generally require.

A Texas law allowed concealed handgun permits but not state-issued IDs for college students or government employees. After Alabama enacted its own statute, Republican Gov. Robert Bentley closed 31 drivers' license offices in mostly black areas that residents needed to visit to get photo IDs, though later agreed to reopen them once a month.

There also is a litany of reasons arguing against a Trump victory, including his attacks on women, Hispanics and Muslims; questions about his business acumen such as his stewardship of three Atlantic City casinos and his role in Trump University; and the fact that several prominent Republicans, including Romney and Bush, won't back him.

Jonathan D. Salant may be reached at jsalant@njadvancemedia.com. Follow him on Twitter @JDSalant. Find NJ.com Politics on Facebook.