New Jersey Gov. Chris Christie (R) leads former Secretary of State Hillary ClintonHillary Rodham ClintonTrump on Booker: 'I know more about Cory than he knows about himself' Michelle Obama urges Dem unity behind Clinton Trump attacks Wasserman Schultz in new web ad MORE in Iowa, according to a new survey from the GOP firm Harper Polling.
Christie leads Clinton in the key swing state by 43 to 38 percent, according to the poll.
Christie and Cruz are tied when Iowans are asked who they'd support. Both get 18 percent, with Paul following at 12 percent and former Sen. Rick Santorum (R-Pa.) holding 10 percent. Ryan has 8 percent support, and Rubio is tied with Wisconsin Gov. Scott Walker (R) at 6 percent.
Some GOP strategists believe Christie might struggle in Iowa's caucuses because he's viewed as more of a centrist and caucus-goers in the state tend to be very conservative, especially on social issues. But the poll shows he might have a real chance at winning there, both in the primary and general election.
Christie's lead over Clinton could be partly due to Democrats' struggles overall in Iowa. President Obama has just a 34 percent job approval rating in the poll, with 55 percent disapproving.
Obama won Iowa in the 2012 election, carrying 52 percent of the vote.
But his popularity has fallen after a tough year in office, and his signature healthcare reform law is similarly unpopular.
While partisan polls should be taken with a grain of salt, this is the latest in a series of surveys that have found Christie is the strongest candidate against Clinton.
For Iowa's open Senate seat, Rep. Bruce Braley (D-Iowa) has small leads over the Republicans running for the GOP nomination — he tops out at 42 percent and holds leads of 3 to 6 points, depending on the candidate. Those numbers show if the GOP can get a strong candidate against the congressman, they might have a real shot at winning the seat.
The automated poll of 985 likely voters was conducted from Nov. 23-24 and has a margin of error of plus or minus 3.12 percentage points.