Biden: Sanders and Buttigieg won't win the long game in 2020

Former Vice President Joe Biden opened the Democratic debate on Friday night by reiterating that while Sen. Sanders (I-Vt.) and Mayor Pete Buttigieg came out on top in the Iowa caucus, they will face problems down the 2020 road.

Thought bubble... Per Axios' Alayna Treene: Biden is playing straight to voters biggest concern with his answer to the first question: Which candidate can best take on Trump on the debate stage and beat him in the general election? Biden says Trump will label Sanders as a socialist, and given the fact that he is one, Republicans will eat him alive

"In regards to Sen. Sanders, the president wants very much to stick a label on every candidate. We're going to have to not only win this time, we're going to have to win the Senate. Bernie has labeled himself, not me, a Democratic socialist. That's the label that's going to weigh on everybody's mind with Bernie if he's a nominee."

"And Mayor Buttigieg is a great guy, and you're a patriot. He's the mayor of a small city who has done some good things, but has not demonstrated his ability to —and we'll soon find out— to get a broad scope of support across the spectrum including African Americans and Latinos."

Go deeper: Buttigieg responds to Biden's electability criticism