Bernie Sanders: Meet the Liberals in Congress Who Are Ready for Him

Progressive congressmen call Sanders a "credible challenger" to Clinton in 2016.

“We're proud that Bernie is going to make this a real race. He's going to bring up some important points, and we believe that it's a good idea to have a spirited discussion on these issues,” Ellison said. “We think this is good news, and we welcome it.”

“I think it's part of a very important dialogue,” said Grijalva of the issues he believes Sanders will campaign on, should he decide to run.

But could the Koch brother-bashing, Wall Street-hating, environmental protest-loving, ultra-liberal senator from Vermont pose a credible challenge to Clinton in the primary?

Added Grijalva, “I think those are issues our base wants to hear about very desperately and I think he's going to bring that to this whole primary.”

As for whether Sanders could actually win the Democratic nomination, Grijalva pointed to common perceptions of the senator that wrongly undermine his credibility as an obstacle for Sanders’ campaign.

“Bernie has unfortunately been many times dismissed as a gadfly, Grijalva said. "The fact that he continues to be elected, [that he] got elected to the Senate, means his ideas have credibility."

But still, Grijalva believes the challenge is surmountable.

“Once we get past the stereotype and listen to what he's talking about, there's a great deal of credibility there,” Grijalva said.