In North Carolina’s Senate race, like everywhere, it’s all about Trump

Patrick O’Brien says he’ll be “first in line” to vote for President Donald Trump again in November. Speaking under a sweltering summer sun, the retired police officer offers multiple reasons why the president deserves to be reelected.

But when asked about Thom Tillis, North Carolina’s first-term senator who will also be on the ballot this fall, Mr. O’Brien pauses and strokes his gray goatee. He then asks, “He’s a Republican, right?”

It’s a common reaction across Nash County, a rural area known for its sweet potatoes, where some streets have more churches than houses. Many voters don’t have a strong opinion about Senator Tillis or his Democratic challenger Cal Cunningham. Instead, the vast majority say they’ll vote based almost entirely on their opinions of President Trump. 

Split-ticket voting has become increasingly rare as the country has become more polarized along partisan lines. In 2016, all 34 Senate races were won by the same party that won the presidential race in those states. And while presidential candidates often have “coattails,” helping elect down-ballot politicians on the strength of their own popularity, the reverse can also be true.

With President Trump, the effect may cut both ways: He inspires passionate levels of support among his party’s base, while also repelling many swing