Sen. John McCainJohn McCainKasich: 'I think political parties are on their way out' Five fights for Trump’s first year Trump wall faces skepticism on border MORE (R-Ariz.) says he is "leaning towards" running for reelection and is well aware he'll likely face a tough primary challenge from the right.
McCain said he has received only encouragement to run but warned supporters he'll be facing a "very difficult campaign."
"I tried to point out to them that we have to expect a very difficult campaign and hope that it's easy. But you always have to plan for a very, very tough campaign with good competition," he said.
Conservatives have long expressed their frustration with McCain for his more centrist record, particularly on immigration reform. He drew a spirited challenge from former Rep. J.D. Hayworth (R) last cycle, which he ultimately dispatched easily despite the strength of conservative challengers in other races nationwide.
He said he's already thinking about the prospect of another primary fight this cycle.
"Oh, I think you can certainly anticipate it," McCain said. "If you're going to win a campaign, you have to plan for all scenarios, including significant primary opposition. I wouldn't like to see it, obviously. Unfortunately, we don't conduct campaigns by unanimous consent.”
He plans to make a decision by early next year, to give him time to prepare for a tough fight.
"Every campaign I've been in, I've said, 'Look, this is going to be the toughest.' You have to assume that. We've seen, historically, that people who take anything for granted, then they put that election in jeopardy. I've never done that," he said.