The final edition of the Reuters/C-SPAN/Zogby daily tracking poll shows a dip for Hillary Clinton, an expanded lead for Mike Huckabee and move by Ron Paul into a tie for fourth place.

At 31 percent, Huckabee now leads Mitt Romney by six points, his largest lead since the first release of the tracking poll on Dec. 30. Fred Thompson, at 11 percent, moved into sole possession of third place, followed by Ron Paul and John McCain at 10 percent.

Barack Obama also registered 31 percent support, 4 points ahead of John Edwards and 7 points ahead of Hillary Clinton.

Pollster John Zogby reminded readers that his poll predicted the 2004 caucus finish: "Edwards finished this Zogby daily tracking in Iowa in the same place as four years ago, when Zogby correctly identified the finishing order of the candidates in that caucus."

- See more in PollWatch
- See the Reuters press release

UPDATE: Talking Points Memo reports that Zogby says Clinton's performance worsens when second-choice votes for non-viable candidates are taken into account:

Here's what they gave us: Obama 37.5%, Edwards 33.7%, Clinton 28.8%.

The pre-reallocation numbers were Obama 31%, Edwards 27%, Clinton 24%, showing that Hillary's deficit only worsened after second choices were taking into account. There is, however, a caveat: The other candidates' voters are naturally a much, much smaller sample set than the sample as a whole, meaning that second-choice calculations carry a very large margin of error.

Labels: Democrats, Republicans