Poll: Scott Walker maintains lead in Iowa

In the GOP presidential race in Iowa, Wisconsin Gov. Scott Walker is holding onto his early lead, while Florida Sen. Marco Rubio has shot up from the bottom of the pack to a tie for second with Kentucky Sen. Rand Paul, a Quinnipiac University poll released Wednesday shows.

Next most popular with likely Republican caucus-goers in Iowa is Texas  Sen. Ted Cruz. Close at Cruz's heels is former Arkansas governor Mike Huckabee, who announced his candidacy on Tuesday.

Walker is the only one from that group who has not yet formally declared his candidacy. Walker's lead has slipped by four points, from 25% down to 21%, since Quinnipiac last polled in Iowa in late February, but he remains strongly at the front of the pack.

Some of the worst news in the survey is for former Florida governor Jeb Bush and New Jersey Gov. Chris Christie. When asked if there is any candidate they would definitely not support, 25% of likely caucus-goers named Bush and 20% said they've ruled out Christie. Those two top this negative list, followed by Paul with 13% who definitely wouldn't back him.

Bush ranks seventh overall in this poll, behind Ben Carson, who registers in sixth with 7% support.

And despite all former Texas governor Rick Perry's hard work in Iowa with repeated visits, he's tied in eighth place with Christie. At the very bottom in this survey are Louisiana Gov. Bobby Jindal and South Carolina Sen. Lindsey Graham.

Quinnipiac surveyed 667 likely caucus-goers from April 25-May 4. The margin of error is plus or minus 3.8 percentage points.

For more on this story, go to The Des Moines Register.