Gov. Scott Walker continues to lead the GOP primary field, despite being one of the only candidates who hasn't announced a bid for president.
For the fourth straight time, Walker leads among Republican candidates with 17 percent in the latest Public Policy Polling survey.
Trailing Walker is Florida Gov. Jeb Bush, who announced his candidacy this week, at 15 percent. Sen. Marco Rubio of Florida has 13 percent, followed by retired neurosurgeon Ben Carson at 12 percent and former Arkansas Gov. Mike Huckabee at 11 percent.
Walker gets a significant bump from voters who describe themselves as "very conservative," earning 23 percent of their support. In that category, he's followed by Carson, at 17 percent.
Former Secretary of State Hillary Clinton, the Democratic frontrunner, leads by a slight margin in match-ups with each Republican candidate. Against Bush, New Jersey Gov. Chris Christie and Walker, Clinton leads by four points.
Fifty-three percent of those surveyed said they have a favorable opinion of Walker, while 34 percent were unsure and 13 percent view him unfavorably.
The left-leaning PPP surveyed more than 1,000 voters between June 11 and 14.