Of note: more Iowa Democrats have a favorable impression of him — and fewer have an unfavorable impression of him — than any other candidate.

Clinton owes her solid standing to strong support from women, voters over age 50, and Democrats who rank health care as their top issue and experience as the most important personal characteristic.

A warning sign: One in five Iowa Democrats have an unfavorable opinion of her, and she ranks low among voters looking for honesty and change.

Obama has the edge among young voters under 30, those looking for a new approach to politics, and honesty. His challenge: low support among those valuing experience most, and convincing people he can win.

Meanwhile, the new McClatchy-MSNBC poll shows the assassination of former Pakistani Prime Minister Benazir Bhutto did not raise the profile of terrorism as an issue in the U.S. presidential campaign in Iowa.

"People are still voting on what they were voting on a week ago," said Coker, the Mason-Dixon Polling & Research pollster.

Democrats still rank terrorism a very low priority. The survey found 5 percent of Iowa Democrats calling it their top concern, up from 1 percent earlier in the month, but with virtually no change during three nights of poll calls that started the evening before the assassination and continued the next two evenings when news of the murder dominated national media.

Republicans still rank it highly, with 29 percent calling it their top issue, down from 31 percent in the previous poll Dec. 3-6.