He would lose everything but Vermont and DC.
Oh it would be a very bad loss for sure however It may not be quite this bad. I think he would lose similiar to how Michael Dukakis lost. In that he would carry something like 10-12 states. He would hold California, New York most of New England and maybe a few other normally solid blue states but still a bad loss well under 200 electoral votes. Polls may say one thing now in terms of competitiveness but I dont see him appealing to anyone in the political center once a campaign started.