The real problem for Bush at this point is not so much that the Clarke revelations and the questions they raise will automatically pay big dividends for Kerry. It's that these developments are eroding Bush’s support at its presumed bedrock: his handling of the war on terror and related issues.

As I mentioned on Saturday, the latest Newsweek poll has Bush's approval rating on handling terrorism and homeland security down to 57 percent. I also mentioned that, at this point, a plurality of voters (42 percent) say they'll be less likely to vote for Bush because of his handling of postwar Iraq, rather than more likely (34 percent).

Here's some more telling detail from the same poll. A plurality of voters (40 percent) also say they’ll be less likely to vote for Bush because of his decision to invade Iraq, rather than more likely (37 percent). Note that two months ago both of these indicators were net positive for Bush–those saying they were more likely to vote for Bush outnumbered those who saying they were less likely.

Even his greatest strength–the response of his administration to the terrorist threat after 9/11–is attenuating as an influence on voters. It is true that today those saying they’re more likely to vote for Bush because of his actions in this area outnumber those saying less likely by a 22 point margin (50-28). But two months ago that same question returned a 39 point Bush advantage (60-21).

And here’s a very significant result: At this point, just 25 percent believe the US military action against Iraq has done more to decrease “the risk that large numbers of Americans will be killed or wounded in a future terrorist attack”. That compares to 41 percent who say the action against Iraq has done more to increase that threat and another 27 percent who say the Iraq action has made no difference.

The public is also now close to split on whether the Bush administration has done all it could to fight terrorism (46 percent) or has not done all it could (43 percent). Note that political independents now believe by 47 percent to 40 percent that the Bush administration has not done all it could.

The same closely-divided public can be seen in a question on whether the attention the attention the Bush administration has given to Iraq has (42 percent) or has not (47 percent) distracted from efforts to fight terrorism. Again, independents are tilted the other way: by 47 percent to 44 percent, they think Iraq has distracted from efforts to fight terrorism.

The key task for Kerry is to turn this apparent erosion in public support for Bush’s handling of the war on terror, along with Bush's increasingly poor domestic ratings (see Saturday's post), into real momentum in his direction. According to most polls, Kerry now has a slight lead in Kerry-Bush trial heats. That’s a start, but Kerry clearly has a way to go before he recaptures a significant advantage in the race.