In early September, James Carville—the political strategist who helped engineer Bill Clinton’s first presidential campaign—explained to Vanity Fair just how much national politics has changed in the past three decades. “In 1992, the most treasured voter was a voter that would sort of swing back and forth, one that might vote for Republican for president, Democrat for governor,” he said. “The voter that didn’t have that strong of a partisan ID. These were the voters that we targeted.”

In contrast, elections these days are all about turnout. The campaigns that wield the best field operations—capable of turning out scores of voters on Election Day and collecting thousands of early ballots in the weeks prior—are more likely to be victorious. The goal is no longer to identify and persuade those in the squishy middle of the ideological spectrum to split their tickets. Instead, campaigns try to find sporadic voters who, if they could be persuaded to go to the polls, would vote straight down the ticket.

One simple fact explains that shift: According to political scientists, that coveted voter from 1992—the one that might have voted for a Democratic president and Republican congressman—basically no longer exists. Only 25 congressional districts in 2012 voted for a president of one party and a House member of the other, down from just over 100 in 1992. It was the first time in 92 years that the percentage of congressional districts that split their tickets dropped into the single digits. And it prompted apocalyptic headlines like this one in The Washington Post: “The ideological middle is dead in Congress. Really dead.”

Four years later, facing the prospect of likely defeat in the race for president, Republicans across the country are betting against the conventional wisdom. In crucial swing states, their electoral hopes rest on the slim chance that some affluent Republican voters dislike Donald Trump enough to split their tickets, backing Hillary Clinton for president and Republicans in the House and Senate. The stakes are highest in the Senate, which the Democrats have a good shot at reclaiming.

But thanks to the sui generis nature of Donald Trump’s candidacy—which has alienated key conservative groups like educated Republicans in the suburbs—the split-ticket voter may very well enjoy an anomalous resurgence this election season. And luckily for Republicans, some of states with the most competitive Senate races in the nation this year have long histories of splitting their tickets. 

Republicans hoping to pull this off, however, are going to have to be adroit in separating themselves from Trump, the man who muddled all these party divisions in the first place. If they need a playbook for how to convince voters to split their tickets, they ought to look to Rob Portman, the mild-mannered Republican incumbent running against former Ohio Governor Ted Strickland, in what was supposed to be one of the tightest Senate races in the country.

National Review’s Eliana Johnson reports that Portman’s field organizers have been handing out literature touting his union endorsements at Clinton rallies in the state. The Teamsters, the International Union of Operating Engineers, the United Mine Workers, the Fraternal Order of Police—they have all endorsed Portman. A Black Lives Matter group even endorsed the Republican senator in late July. That has helped Portman cast himself as a crossover candidate—and insulated him from the vagaries of the national political climate.

The last time Ohio voted for a Senate candidate of a different party than its presidential choice was way back in 1988, when it backed George H.W. Bush and Democrat Howard Metzenbaum. But this year, Portman’s split-ticket strategy seems to be working. He is up by nearly 15 points on Strickland, according to Real Clear Politics’s polling average. The margin is wide enough that the Democratic Senatorial Campaign Committee recently diverted funds away from Ohio, canceling two additional weeks of ads there. It’s a sign that, at least for now, the national Democrats have given up on flipping the state, even as they hope Clinton can put Ohio in the victory column.

Pat Toomey of Pennsylvania, however, is having a tougher time. Since he was elected during the Tea Party wave in 2010, Toomey has studiously moved towards the middle, spearheading bipartisan gun control legislation with West Virginia Senator Joe Manchin. In this purplish state, his carefully cultivated moderate stances should have been enough to send him back to Washington this fall—until Donald Trump intervened.

Trump is popular in the conservative steel towns in central and northern Pennsylvania, and Toomey needs those voters in November. But he also needs to clinch the handful of suburban districts that ring Philadelphia, the swing districts in most statewide races. Voters there are wealthy, white, and have college degrees—all indicators that Trump will have a hard time winning them over. Toomey therefore needs to convince those voters to split their tickets, backing Hillary Clinton for president and him for Senate. (Clinton is currently up in Pennsylvania by a fairly comfortable six points.)

It all hinges on portraying himself as a crossover candidate, much like Rob Portman. But Toomey has had a harder time separating himself from Trump—in part because denouncing him might drive his Republican base away. His attempts to differentiate himself from the nominee have been wishy-washy at best. When The Washington Post asked him whether he would endorse Donald Trump in August, he replied that he was “still learning things about this nominee.” 

Meanwhile, challenger Katie McGinty is bent on yoking Toomey to Trump. For now, it seems to be working. In the aftermath of the Democratic National Convention in Philadelphia, when McGinty delivered a speech tying her opponent to the Republican nominee, she climbed into the lead. Real Clear Politics now has her running neck and neck with Toomey. His best bet would be to continue arguing that keeping the Senate in Republican hands would act as a check on a President Clinton.  

New Hampshire, like Pennsylvania, has a history of split-ticket voting. The Granite State elected a senator from a different political party than its presidential choice seven times in the last century, or 44 percent of the time. The state did so as late as 2004, when it backed John Kerry for president and Republican Senator Judd Gregg. That ought to be good news for Kelly Ayotte, the Republican incumbent.

But there is a chance she will lose her Senate seat to Democratic Governor Maggie Hassan. Like Toomey, Ayotte has struggled to put daylight between herself and the Republican nominee, while keeping her Republican base placated. Trump won the New Hampshire Republican primary in spectacular fashion back in February, carrying more than 100,000 votes. No other candidate even came close. She needs to make sure she can shore up their support. 

But she’s in a tough position. Her husband was in the military, and she’s a woman. Without speaking out against what Trump has said about Gold Star families, veterans, John McCain, and women in this campaign and beyond, she risks looking disingenuous. She and Hassan are essentially tied in the polls, even as Clinton leads by five points.

Iowa Senator Chuck Grassley is in a far better position than Ayotte. He may well outperform Trump in Iowa, a state where the Republican nominee is already up around four points. “Iowans have a tendency to split their tickets between Republicans and Democrats, and that tendency has almost always benefited Grassley,” The Des Moines Register wrote in late August. The Republican senator, first elected in 1980, has “received tens of thousands of votes from registered Democrats” over his 36 years in the Senate, often outperforming the other Republicans competing in statewide races there (in 2004, he won 286,218 more votes than George W. Bush). 

In one sense, Marco Rubio may be in the strongest position of all these Republican establishment figures banking on split-ticket voters to hang on to their Senate seats. He has the distinct advantage of spending months during the Republican primary ridiculing Donald Trump in the hopes that it would stop him on his glide path to the Republican nomination. “You know what they say about men with small hands,” he said at a Republican debate. He followed it up with similar salvos: “Donald is not going to make America great, he’s going to make America orange.” He also called Trump a “con man.” If Rubio wanted to differentiate himself from the Republican nominee, that ought to have done the trick.

Back in the spring, his campaign and network of super PACs also advertised heavily in Florida, in Cuban-American districts like Miami-Dade, claiming Rubio as a native son. One ad, narrated in Spanish, begins: “This time we can make one of our own be the next president. Marco Rubio, proud son of Miami. He knows our streets. Our communities. Our passions. Understands our dreams. Believes in our future. Because he has never forgotten where he comes from.” The Hispanic voters in Florida will likely be the crucial demographic swinging Florida to Clinton, who is essentially tied with Trump in the Sunshine State. But Rubio, a proud son of Miami, may have an even stronger claim to their votes. Like other candidates hoping to split the ticket, Rubio is using local connections and local issues to his advantage.