Mitch Stewart, a senior adviser for Ready for Hillary, said it is time for Democrats to admit their party "got slaughtered" in the 2014 midterm elections.
"Number one, Chris, is we got slaughtered," Stewart told MSNBC's Chris Hayes. "I think it's important for Democrats to recognize that."
Aside from the "structural problem" of the influence of outside money in the elections, Stewart said Democrats had a severe messaging problem.
"The biggest takeaway going into this election is that our message, Democrats' message to middle class voters on the economy, has not worked," Stewart said.
Stewart is a founding partner of 270 Strategies, which was instrumental in the failed campaign to elect Democratic gubernatorial candidate Wendy Davis and "turn Texas blue."