"A poll for Obama"

Ben Smith:

Obama got the boost that he -- and perhaps that a media looking for this to turn into a head-to-head between him and Clinton -- needed from Newsweek today: A poll that has him, for the first time, up in Iowa.

Among all Iowa Democratic voters, Clinton draws 31 percent, followed by Obama (25 percent) and Edwards (21 percent). But among likely caucus-goers, Obama enjoys a slim lead, polling 28 percent to best Clinton (24 percent) and Edwards (22 percent). Bill Richardson is the only other Democratic candidate to score in the double digits (10 percent).

Worth keeping in mind people who say they're "likely" to caucus is still a looser screen than one might like,* and also that according to the poll, his support isn't as strong as Hillary's.

Still, it suggests that his expensive new advertising push there could be making a dent, and it puts a bit of a damper on Hillary's inevitability.

UPDATE: Actually, it's the second poll with Obama up. The other was the August 3 ABC/Washpost survey. And details of the screen, which I'd initially misread, are here: it's registered Iowa Democrats who say they'll "definitely" or "probably" attend, and captures mostly repeat caucus-goers, a sign that it's a tight screen.