“It’s a different Senate today. The challenge for him will be there are so many new senators and where that center of gravity lands, I think it’s too early to tell,” said Sen. Martin Heinrich (D-N.M.), who arrived in the Senate in 2013, four years after Biden had left to become vice president.

“I have a lot of respect for him. …” said Heinrich, who is 47. “My bias is that we have this new, incredible generation of leadership and that in 2020, my hope is that the race will reflect that and I would like to see the nominee reflect that.”…

“There may be quite a few Senators who vote with their hearts,” said one longtime Senate aide, adding that it will be an “uphill climb” for Biden.

Sen. Richard Blumenthal (D-Conn.) said he and Biden are “friends” but that he has not heard from the vice president in awhile.