The super-PAC plans a $16.25 million ad blitz to help Walker's lagging support.
Trump said he will not change his mind about the pledge.
Captain Crunch leads PPP's survey of "joke candidates."
It is only Clinton's third sit-down interview of the 2016 cycle.
“Personally, I don’t think it should be legal,” the 2016 GOP front-runner said.
Snowden also dismissed comments by Donald Trump, who called him a "traitor."
It's part of a $7 million ad buy in Iowa.
In a distant second place is Ben Carson with 18 percent support.
The Minnesota Republican has announced he will not seek reelection.
Jordan Fabian 09/03/15 11:46 AM EDT
The vice president touted his relationships with world leaders ahead of a possible White House...