An Associated Press / Pew Research Center poll of likely voters in three early primary states finds Hillary Clinton leading Barack Obama by substantial margins in New Hampshire and South Carolina, but by just 5 points in Iowa. John Edwards registered in double digits in each state, but trailed Clinton by large margins in all three.

One note: the poll was conducted from November 7-25, whereas most polls released during the past week (which show Clinton’s lead slipping) were conducted over a more recent three or four day period. The methodological strength of polling over 3.5 weeks is that the results are not skewed in light of any particular events that may soon fade from the consciousness of the electorate (this is one of the reasons polls are usually not conducted over just one day).

The danger of the new AP/Pew poll is that its polling period is so long, dating back nearly a month, that it waters down the possibility of genuine voter attitude change that has occurred during the past week toward the Clinton campaign. If, for example, AP/Pew releases new Republican polling numbers later this week, one would thus expect that Mike Huckabee’s measured support to be not as strong than it is in the other polls that have flooded the news cycle during the past week.

With that disclaimer, here are the new numbers:

In Iowa:

Clinton = 31%
Obama = 26%
Edwards = 19%
Richardson = 10%
Biden = 2%
Dodd = 1%
Kucinich = 1%
No opinion = 9%

In New Hampshire:

Clinton = 38%
Obama = 19%
Edwards = 15%
Richardson = 10%
Kucinich = 4%
Biden = 2%
Dodd = 1%
No opinion = 10%

In South Carolina:

Clinton = 45%
Obama = 31%
Edwards = 10%
Biden = 2%
Kuninich = 1%
Richardson = 1%
Dodd = 0%
No opinion = 10%