Political strategist James Carville said on MSNBC on Saturday that choosing Sen. Bernie Sanders to go up against President Donald Trump would be political suicide. 

Carville said on MSNBC that he was worried the media is not evaluating the risks to voters of nominating Sanders as the Democratic candidate. 

“The entire theory that by expanding the electorate, increasing turnouts, you can win elections, is the equivalent of climate denying. When people say that, they are as stupid to a political scientist as a climate denier is to an atmospheric scientist,” he said.

Carville continued to say that he understood why voters were drawn to Sanders, but added, “If you’re voting for him because you think he’ll win the election, because he’ll galvanize heretofore sleepy parts of an electorate, then politically, you’re a fool. And that’s just a fact.”

“It’s no denying it, there’s so much political science, so much research on this that it’s not even a debatable question. And if people are appraised of this, and they know that, and they want to do it as Democrats, that’s their own business. But I don’t think they have all the facts that they need before they make this judgment going forward,” he added.

When asked by MSNBC’s Nicolle Wallace if he was describing political suicide, he simply answered, “It is.”