Delaware Republicans haven't coalesced behind Senate candidate Christine O'Donnell (R), who continues to trail Democrat Chris Coons in two new polls.

Only 68 percent of likely Republican voters say they plan to back O'Donnell, according to Fairleigh Dickinson University poll released Wednesday.

O'Donnell defeated Rep. Mike Castle, a party stalwart, in last month's GOP Senate primary. Castle declined to endorse her after the vote.

Meanwhile, Democrats are united behind Coons — 85 percent of the party's likely voters said that they will vote for him in November.

"Typically, Republicans are more loyal to their party than Democrats," Dan Cassino, a professor at Fairleigh Dickinson University and a survey analyst, said in a statement. "This hesitation by Republicans is hurting O'Donnell."

Overall, Coons leads O'Donnell 53 percent to 36 percent, but he's in a statistical dead heat with Coons in Kent and Sussex counties. In the state's biggest county, New Castle, Coons leads by a margin of 58 percent to 31 percent.

The university polled 801 randomly selected likely Delaware voters by telephone from Sept. 27 through Oct. 3. The survey has margin of error of plus or minus 3.5 percentage points.

A University of Delaware poll released Tuesday found 49 percent of registered voters supporting Coons and 30 percent supporting O'Donnell.