One place he will not speak, having addressed the past six Republican conventions, is inside Quicken Loans Arena, where Donald Trump will accept the nomination of the most divided national party of modern times.

On two mornings, he will remodel houses in inner-city Cleveland with Habitat for Humanity. On Tuesday, he will kayak on the Cuyahoga River with wounded veterans. As the convention is gaveled to order on Monday afternoon, Portman, a Republican facing a tough re-election fight, will address hundreds of his campaign volunteers at a community college.

CLEVELAND — US Senator Rob Portman of Ohio plans a very busy convention week as Republicans pour into his home state beginning Monday.


Portman once looked forward to a convention in Cleveland that would turbocharge his re-election campaign. Now he joins other swing-state Republican senators who are shying away from the party gathering. They will be busily campaigning at home, running local races as if for sheriff, offering a split-screen view of a party that fears its Senate majority will be the collateral damage of a polarizing nominee.

The convention avoiders include six of seven senators on the ballot in states where President Obama won twice. (The lone attendee, Charles E. Grassley of Iowa, has said he plans a "fast in, fast out" visit.)

Their survival strategy is to focus on home-state issues that in voters' minds place them as far as possible from Trump.

"Localize, localize, localize," said Whit Ayres, a Republican pollster, offering the mantra of endangered Senate incumbents on the same ballot as Trump.

Portman and Kelly Ayotte of New Hampshire are highlighting their co-sponsorship of a bill to fight opioid addiction that Congress passed last week, an issue of intense concern in their states — and which few associate with the name Trump.

Patrick J. Toomey of Pennsylvania, also skipping the convention, is visiting 13 counties in his state, where he has attacked Philadelphia's liberal mayor for refusing to cooperate with federal immigration authorities.


Marco Rubio of Florida has seized on an issue unmentioned when he ran in the presidential primary: toxic algae blooms in state waters.

During the convention, Rubio will campaign in Florida, in Fort Myers, Orlando, Tampa, and elsewhere.

Democrats have no intention of letting Republicans escape from the penumbra of Trump. Toomey's opponent, Katie McGinty, bashed the "Trump-Toomey ticket" on Saturday. Portman's Ohio opponent, Ted Strickland, is sending eight supporters dressed as Supreme Court justices to heckle Portman's event on Monday.

"They will highlight how Portman will help Trump reshape the court for generations," said David Bergstein, a spokesman for Strickland.

"Trump is a total nightmare for Rob Portman," said Rebecca Pearcey, Strickland's campaign manager.

In fact, most down-ballot Republicans cannot afford to completely distance themselves from Trump. They will need his supporters in the fall, while also attracting independents and Republicans who say they will abstain from voting for either major party's presidential nominee.

Some senators have tried to split hairs, like Ayotte, who says she "supports" Trump as the party's nominee but does not "endorse" him.

Only Mark S. Kirk of Illinois, one of the most vulnerable Republican senators this year, running in a heavily Democratic state, has disavowed Trump, calling him "too bigoted and racist" to be president.

Portman, long a favorite of the Republican establishment, said in an interview that he would vote for Trump, but was not sure that he would find time to campaign with him in Ohio.


He and the other convention avoiders are hoping for a resurgence of split-ticket voting, capturing the votes of Republicans and independents who do not support Trump.

The problem is that ticket splitting has declined for decades as voters have become more polarized. It was last a factor in the 1980s, when Southern Democrats voted for Ronald Reagan and for Democratic House members and senators.

Trump's divisiveness could mean a return to ticket splitting, Republican strategists said. "We're starting to see hints of the largest amounts of split-ticket voting since the 1980s," Ayres said.

Recent polls in swing states show Republican senators with more favorable margins against their Democratic challengers than those separating Trump and Clinton. The early polling suggests some voters who do not support the Republican presidential nominee back the party's senators.

A Quinnipiac survey of Ohio that showed Trump and Clinton tied last week found that Portman led Strickland by 7 percentage points. In Florida, the same poll had Trump leading by 3 percentage points, but Rubio with 12- and 13-point advantages over potential Democratic challengers for his Senate seat.

Thanks to the brutal Republican primary campaign in Florida, during which Trump and Rubio traded insults, Florida voters already have strong impressions of how they differ.

"There was a two-week stint in March where the differences between the two were very well litigated," said Alex Conant, an adviser to Rubio. "Voters know he's not Donald Trump."


As he campaigns in Ohio, Portman, 60, spares no occasion to raise the threat of opioid abuse, a signature issue that establishes him as his own man, while fending off his opponent's most dangerous attack: his long history as a free-trade supporter, putting him at odds with Trump's base.

Portman has visited a dozen drug treatment centers in the past month. "People are seeing, OK, this is a little different kind of Republican," he said in his campaign RV recently as it rumbled between Dayton and Toledo.

He was one of four Senate authors of a bipartisan opioid treatment bill, one of Congress' few accomplishments this year, which last week moved to Obama's desk.

Portman, a mild-mannered Washington insider who defied his party by embracing same-sex marriage in 2013 after learning that one of his sons was gay, sighed when asked if Trump had the right temperament to be president. "We're different," he said. "That doesn't mean my temperament is right for the presidency, or his is wrong."

Strickland, his opponent, wants voters to hear more about Portman's stint as the country's top trade negotiator under President George W. Bush. "The Best Senator China Ever Had," the Strickland campaign labeled Portman, accusing him of failing to stop the illegal "dumping of steel."

PolitiFact determined that the attack was false. But the nuances may go over voters' heads in a year when Trump has made China and American trade deals the culprits for lost factory jobs.


"What the Trump campaign is going to do is shine a spotlight on Portman's trade record that's not going to work with Ohio voters," said Pearcey, the campaign manager for Strickland.

Portman said he agreed with Trump about cracking down on China for dumping steel. But he strongly defended the economic benefit of free-trade deals to Ohio's economy. "We have 25 percent of our factory workers" making goods for export, he said. If tariffs are erected in a trade war, as many experts believe Trump's policies would spur, "farmers would see their prices totally crater," Portman said.

"I think he's just wrong," he said of Trump.