The Concord (N.H.) Monitor poll results indicated the Democratic race could depend undeclared voters who aren't registered with either party, the Monitor reported Friday. In New Hampshire, undeclared voters can vote in either party primary, scheduled for Jan. 8.

Of the likely Democratic primary voters surveyed, 37 percent were undeclared voters. They favored the Obama, D-Ill., over Clinton, D-N.Y., 40 percent to 23 percent. Former Sen. John Edwards, D-N.C., was third with 13 percent.

Among registered Democrats, Clinton had more support -- 36 percent saying they'd vote for Clinton, compared with 27 percent for Obama and 21 percent for Edwards.

On the Republican side, former Massachusetts Gov. Mitt Romney maintained his lead over his GOP rivals. Romney captured 31 percent over former New York Mayor Rudy Giuliani and Sen. John McCain, R-Ariz., who polled 18 percent and 17 percent, respectively. Former Arizona Gov. Mike Huckabee earned 9 percent.

In conducting the poll for the Monitor, Research 2000 interviewed by telephone 600 likely voters. The poll has a 4 percent margin of error.