Ralph Freso / AP

The effect of Donald Trump’s candidacy on down-ballot races has concerned Republicans, worried his divisive rhetoric might alienate conservative voters. But on Tuesday night, John McCain eased those fears with his victory in Arizona’s Senate primary.

Incumbents have won almost all of this year’s contested primaries. In Alaska, Republican Senator Lisa Murkowski won with more than 50 percent of the vote, as did Republican Senator Richard Shelby in Alabama and Representative Todd Young in Indiana. But each such win holds extra weight in a year that’s revealed the fractures within the Republican Party. McCain defeated Kelli Ward by a significant margin on Tuesday night, according to the Associated Press.

Ward, who is aligned with the Tea Party movement, attacked McCain for his age and raised questions about his commitment to support the Republican nominee in the lead-up to the election. She resembled other outside candidates looking to oust establishment Republicans. Ward embraced Trump’s position on immigration, a point of contention with McCain, who in the past worked with Republican and Democratic senators to try to pass comprehensive immigration reform.

But even if “Trumpism” isn’t taking off, as evidenced by Ward’s loss, among others, Trump is presenting a challenge to down-ballot candidates straddling traditional conservatism and Trump’s proposals to avoid alienating his supporters. McCain, who’s running for his sixth term, is now among them. Though he secured a victory in Arizona on Tuesday, he still faces his toughest reelection battle yet against his Democratic challenger, Ann Kirkpatrick. McCain has to keep Trump at arms length to appeal to anti-Trump Republicans, but not do so in a way that alienates those supporting the nominee. It’s an awkward position for the Arizona senator, who has had a rocky relationship with Trump.

Trump said last year that McCain was not a war hero despite being a prisoner of war. Still, the Arizona senator, with reelection on the horizon, backed the nominee. Trump, for his part, had withheld his support of McCain, saying in a Washington Post interview earlier this month: “I’ve never been there with John McCain because I’ve always felt that he should have done a much better job for the vets.” Trump eventually endorsed McCain. But the episode showcased the underlying tension between the two, likely to last until November.

McCain has expressed concern about Trump alienating Latino voters, who make up roughly 22 percent of the Arizona’s registered voters. Earlier this year, McCain said, according to a Politico report, “If Donald Trump is at the top of the ticket, here in Arizona, with over 30 percent of the vote being the Hispanic vote, no doubt that this may be the race of my life.” But Trump, too, has established ties in the state. He received the support of Maricopa County Sheriff Joe Arpaio and won the state’s primary in March. On Wednesday, Trump will be back in the state to deliver a speech on immigration.

The issue is a sensitive one for McCain. In 2013, the Arizona senator was part of the Gang of Eight, which proposed legislation that would provide a path to citizenship. The issue holds particular resonance in Arizona, where, in 2012, immigrants made up 13.6 percent of the state’s population. And McCain has shown no intention of ditching his party’s nominee. “No. There’s no reason to do that,” he said in an interview with Politico. “They all know me. Everybody in Arizona really knows me unless they just moved in.” In any case, he might not have a choice. As Mother Jones argued this month, the challenge for McCain is that he’s fighting for reelection in Trump’s party, an obstacle course in it of itself.

Amid a string of controversies dogging the Trump campaign earlier this month, some Republicans called on the party’s national committee to divert funds to down-ballot races. “We believe that Donald Trump’s divisiveness, recklessness, incompetence, and record-breaking unpopularity risk turning this election into a Democratic landslide, and only the immediate shift of all available RNC resources to vulnerable Senate and House races will prevent the GOP from drowning with a Trump-emblazoned anchor around its neck,” read an open letter to the RNC signed by more than 70 Republicans. Donors have also shifted their attention from the executive to legislative races. The goal: to secure a Republican Congress.

In the general election, McCain will face U.S. Representative Ann Kirkpatrick, who ran uncontested in Arizona. Since she did not face a primary challenger, Kirkpatrick has been able to focus on McCain, criticizing him for his endorsement of the party’s nominee. Kirkpatrick has roughly $2 million cash on hand, trailing behind McCain with some $5 million in his war chest, according to the Federal Election Commission.

So far, a CNN / ORC poll has McCain leading Kirkpatrick by 13 points. But it’s hanging on to a lead and juggling a fragile party that’ll be the challenge.

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