Republican lawmakers and campaign committees have jittered with excitement over the prospect of  Vermont Sen. Bernie Sanders, an avowed “democratic socialist,” winning the Democratic presidential nomination and dragging down-ballot Democrats to their doom, but Senate Majority Leader Mitch McConnell has stayed true to form, prevaricating and lowering expectations.

“I think Republicans speculating about which Democratic candidate for president being easiest to beat may be a bit foolish,” the Kentucky Republican told reporters Tuesday.

“I’m reminded of when the Democrats back in 1980 were all pulling for Ronald Reagan to be the nominee because they thought he’d be the easiest to beat,” he said. “I think it’s going to be a tough general election with a lot of energy on both sides. … For myself, I’ll leave it up to the Democrats to pick who they’d like to be their candidate.”

McConnell has kept a measured tone about Republicans’ prospects for keeping both the White House and a Senate majority, even in the aftermath of some significant political victories.

Though he took a victory lap after defeating impeachment in the Senate earlier this month and was quick to point out President Donald Trump was enjoying his highest approval ratings in some polls since he took office, McConnell acknowledged that “many things will occur between now and the fall.”

“I don’t think there’s any resting on laurels,” he said less than a week after Trump’s acquittal in the Senate. “This is going to be a very competitive race this fall, not only for the presidency but for the Senate as well.”

Other Republicans aren’t being so cautious.

McConnell’s top deputy, Senate Majority Whip John Thune, speculated this week on Sanders’ potential effect in crucial parts of the country for Democrats.

“I would think that in a lot of those swing states it’s a very complicated factor to have him at the top of the ticket if you’re a down-ballot Democrat running for House or Senate, I would be really concerned,” the South Dakota Republican told The Hill.

Some incumbent Senate Republicans are already tying their potential Democratic opponents to Sanders. Arizona GOP Sen. Martha McSally launched a television ad last week titled “Bernie Bro,” linking her likely general election opponent, Mark Kelly, to the Vermont senator. 

“Kelly and Sanders: too liberal for Arizona,” the narrator says in the 30-second spot. The ad references Kelly’s comments on Feb. 14 when he was asked at a campaign event whether he would support Sanders if he becomes the party’s nominee.

“We’re going to see,” said Kelly, a Navy veteran and former astronaut, according to the Arizona Republic. “I will ultimately support who the nominee is of the Democratic Party, that’s clear.”

Arizona’s Senate race is expected to be one of the most competitive in the country in 2020. Trump carried the state by just 3 points in 2016. Inside Elections with Nathan L. Gonzales rates the race a Toss-Up.

It remains unclear whether a Sanders nomination would have the universal negative effect on House and Senate Democrats that many Republican groups are predicting.

Inside Elections downgraded Republicans’ chances of victory in nine congressional districts over the weekend, compared to six races in which they were upgraded. That’s despite Sanders’ victory in the Nevada caucuses.

Senate Minority Leader Charles E. Schumer signaled support for Sanders on Tuesday should the Vermont independent, who caucuses with Democrats, become the party’s presidential nominee.

“We have a lot of strong nominees. We have a lot of Senate candidates running [for president]. I’m not supporting one over the other. But I think every one of them would beat President Trump,” Schumer said.

Bridget Bowman contributed to this report.