For Cardon, who has hoped to play the conservative, outsider alternative to Flake, the poll included another ominous sign: Flake does better among Tea Party voters and those who self-identify as very conservative than he does with the GOP base as a whole. Flake has also picked up the support of the conservative Club for Growth.

{mosads}The poll didn’t ask about the Democratic field in the Senate race, in which Don Bivens, the former state party chairman, and Richard Carmona, a former U.S. surgeon general, are squaring off.

Arizona also gets added to the growing list of states where polls show Newt Gingrich in the lead in the GOP presidential race. The former House Speaker took 28 percent, putting him 5 points ahead of Mitt Romney, while Herman Cain has dropped to third place with 17 percent.

The poll of 400 Republican primary voters was conducted Nov. 17-20 using automated telephone interviews and had a margin of error of plus or minus 4.9 percentage points.