On the heels of winning the Democratic presidential primary in West Virginia, a week after a triumph in Indiana, Bernie Sanders attempted to take a victory lap early Wednesday afternoon on MSNBC. But while host Andrea Mitchell did begin with acknowledgement of the senator’s wins, she was quick to throw cold water on any progress the distant underdog candidate might have made.

For one, Mitchell noted that Sanders came out of West Virginia with the same number of delegates as Hillary Clinton, once you consider the superdelegates, meaning the state did nothing to help him catch up. And secondly, she challenged his notion that he would be the better general election candidate by pointing to exit poll data in West Virginia that claims a third of his supporters there would actually vote for Donald Trump in the fall.

But the line of questioning that seemed to get under Sanders’s skin the most came when Mitchell confronted him on how his determination to stay in the race until the Democratic National Convention this summer could hurt Hillary Clinton in the long run.

“Isn't the bottom line between you and Hillary Clinton and who would be the stronger candidate, that she is now fighting a war on two fronts, getting beaten up by Donald Trump on a daily basis?” Mitchell asked. She noted that despite the fact that Trump has now introduced a new “Crazy Bernie” nickname for the Vermont senator, “he has been embracing you, building you up, he likes the fact that you’re taking her down.”

“So she’s fighting Donald Trump, she’s fighting Bernie Sanders,” the host continued as Sanders interrupted her with a plea of “one second, one second, one second.” He cut her off just as she began to say that the war on two fronts is “depressing” Clinton’s overall support.

“Andrea, I don’t accept that proposition,” Sanders shot back. “Last I heard, Hillary Clinton is running for president of the United States. I am running for president of the United States. Trump is running for president of the United States, and what a candidate does is make his or her best case to the American people.”

“I have gotten attacked and attacked and attacked. My record has been misinterpreted and lied about,” he continued. “The issue of this campaign is to go out to the American people and talk about why the American people are struggling.”

When Mitchell continued to argue that Clinton is being forced to take on two candidates when he only has to challenge one, Sanders let out a sharp laugh and replied, “Oh, really? Really? In every state that we have won, in 19 states, we have had to take on the entire Democratic establishment. We’ve had to take on senators and governors and mayors and members of Congress. That’s what we have taken on, so please do not moan to me about Hillary Clinton’s problems.”

“I don’t think I was moaning about Hillary Clinton’s problems,” Mitchell said, defending herself before she played a clip of Trump using Sanders’s words to attack Clinton on Morning Joe. “If you do lose, are you giving him the weapons against her?”

“If Donald Trump wants to take my ideas and fight for a single-payer national health care program,” Sanders said, laughing again, “or wants to fight to make sure that the wealthiest people in this country, like Donald Trump, start paying their fair share of taxes, wants to make sure we have paid family leave, wants to raise the minimum wage to 15 bucks an hour, rebuild our crumbling infrastructure, if that is what Donald Trump is supporting, I think that’s a good thing and I hope Hillary Clinton does that as well.”

Of course, as Sanders ultimately admitted, Trump will most likely do none of those things whereas he has already pushed Clinton to embrace the majority of his positions. The candidate defended himself further by reminding Mitchell that he has refrained from attacking Clinton on a number of issues that were ripe for criticism.

The delegate math may be entirely in Clinton’s favor, but as Sanders continues to make clear, he’s not going anywhere soon. As as Andrea Mitchell learned today, suggesting that he is helping Donald Trump is not going to convince him otherwise.