Poll: Huckabee's lead continues in Iowa
© Greg Nash

Former Arkansas Gov. Mike Huckabee (R) continues to lead early polling in Iowa for the GOP presidential race in 2016. 

Huckabee, who won the first-in-the-nation GOP caucus in 2008, topped a list of potential 2016 GOP candidates, with 20 percent saying they would most likely vote for him if he decides to run, according to a survey by the Democratically affiliated Public Policy Polling released Thursday. 

A February survey from PPP had Huckabee polling at 17 percent, inside the 5.6 percent margin of error. 

Sen. Ted CruzTed CruzSenate passes dozens of bills on way out of town Senate passes stopgap funding bill, averting shutdown Senate advances funding measure, avoiding shutdown MORE (R-Texas) trailed closest behind, with 15 percent. Former Florida Gov. Jeb Bush scored 12 percent and Sen. Rand PaulRand PaulTrump stumps for Louisiana Senate candidate ahead of runoff Giuliani won't serve in Trump administration Will justice in America be Trumped? MORE (R-Ky.) took in 10 percent. 

All other candidates scored in single digits: New Jersey Gov. Chris Christie (9 percent), Wisconsin Rep. Paul RyanPaul RyanRyan appears on Hannity's show President Obama should curb mass incarceration with clemency Senators move to protect 'Dreamers' MORE (8 percent), Wisconsin Gov. Scott Walker (6 percent), Florida Sen. Marco RubioMarco RubioSenate clears water bill with Flint aid, drought relief What Trump's Cabinet picks reveal House passes water bill with Flint aid, drought relief MORE (4 percent) and former Pennsylvania Sen. Rick Santorum (3 percent).

Another 13 percent of Republicans were undecided.

Huckabee has the highest favorable rating among Republicans, at 70 percent. Fourteen percent have an unfavorable view of him.

Christie has the only favorable rating that is underwater. Thirty-six percent of Republicans have a favorable view of him, while 38 percent have an unfavorable view. Another 27 percent were not sure. 

On the Democratic side, 59 percent were most likely to select Hillary Clinton for the Democratic nomination, leading all other candidates by more than 45 points. Vice President Biden garnered 12 percent. 

Clinton leads all Republicans in a potential head-to-head general election match-up. Paul and Huckabee both shrink Clinton's lead to 4 points. 

The poll surveyed 912 registered voters in the state from May 15-19 and has a 3.2 percent margin of error. The margin increases to 5.2 percent and 5.6 percent for Democratic and Republican samples, respectively.