Senate Majority Leader Mitch McConnell (R-KY) is warning Republicans to ease up on their dismissal of Sen. Bernie Sanders (I-VT), cautioning it “may be a bit foolish” to assume he would be the easiest Democrat candidate for President Trump to defeat.

McConnell told reporters on Tuesday the GOP should proceed with caution in goading Sanders’ supporters and assuming the socialist senator leading the ticket would make it easier for the GOP to maintain a majority in the Senate. The Senate majority leader compared the situation to Democrats dismissing former President Ronald Reagan in 1980.

“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,” McConnell told reporters, according to Politico.

“I think it’s going to be a contested general election with a lot of energy on both sides, and for myself, I’ll leave it up to the Democrats to pick who they’d like to be their candidate,” he added.

McConnell’s remarks come on the heels of internal polling commissioned by the National Republican Congressional Committee (NRCC), which indicated that a Democrat ticket featuring the socialist senator could effectively pave the way for the GOP to take back the House.

As Breitbart News reported:

A Politico report found that voters in swing districts targeted by Republicans and Democrats remain skeptical of the democratic socialist, with 42 percent approving of the Vermont senator and 53 disapproving. The NRCC survey found that voters prefer Trump 48 to Sanders’ 43 percent. The outlet reported that the survey has given “fresh hope” to Republicans, who were previously skeptical of the president’s prediction that House Republican Leader Kevin McCarthy (R-CA) will be the next speaker of the House. Politico also wrote that Republicans believe they can target Democrats as “socialists” during the 2020 elections.

It is not just Republicans who feel that way. House Majority Whip James Clyburn (D-SC) said during a recent appearance on ABC’s This Week a Sanders ticket could put the Democrats’ House majority in jeopardy.

“I do believe it will be an extra burden for us to have to carry. This is South Carolina, and South Carolinians are pretty leery about that title socialist,” he said on Sunday, adding that it would be a “real burden for us in these states or congressional districts that we have to do well in.”

“If you look at how well we did the last time and look at the congressional districts, these were not liberal or what you might call progressive districts,” Clyburn stated.

“These are basically moderate and conservative districts that we did well in, and in those districts, it’s going to be tough to hold onto these jobs if you have to make the case for accepting a self-proclaimed Democratic Socialist,” he added.

Sanders’ rise is causing concern among moderate and establishment Democrats, who also believe he will hurt their case down the ballot.

“We’re going to get absolutely wiped out,” Rep. Juan Vargas (D-CA) told Politico.

Despite the concern over Sanders’ open embrace of socialism, McConnell told reporters all of the Democrat candidates are “very, very far to the left.”

“If you look at what the various candidates for president on the Democratic ticket are saying, not a whole lot of difference between any of them — they all look pretty much the same to me,” he told Politico.

“It looks like moderate Democrats are an endangered species or may have disappeared already,” McConnell added.