good analysis of recent polling trends....
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An ABC News/Washington Post survey released on Tuesday recorded a five-point lead among registered voters for Mr. Bush over Mr. Kerry when Ralph Nader was offered as a choice (48 percent to 43 percent to 6 percent) and a one-point lead when the matchup was narrowed to President Bush and Senator Kerry (49 percent to 48 percent). In a USA Today/CNN/Gallup poll released the same day, Mr. Bush led Mr. Kerry 47 percent to 44 percent, with Mr. Nader drawing 5 percent. Without Mr. Nader it was Mr. Bush over Mr. Kerry 50 percent to 46 percent. The next day, a poll from Investor's Business Daily confirmed the trend, showing Mr. Bush at 44 percent, Mr. Kerry at 40 percent and Mr. Nader at 4 percent.
The reaction was predictable. Mr. Bush's chief campaign strategist bragged that the president had defied the "pundits" with his strong position, while Democrats were crestfallen. If Mr. Kerry can't hold onto a lead during one of the worst stretches of the incumbent's presidency, they whispered, how can he defeat Mr. Bush when things get brighter for the president?
But Democrats should pause before they give up — and Republicans shouldn't celebrate quite yet. President Bush's vulnerabilities remain, even if they were not as apparent in this week's polls as they were in previous surveys; the question is whether Mr. Kerry can exploit them.
In none of the polls this week that purported to show the Bush surge does the president have majority support. Any politician running for re-election sweats when a poll shows him under 51 percent.
Voters who say they are undecided almost always end up opposing the incumbent — they know him well, and if they were going to vote for him, they would have already decided. Thus support for Mr. Bush should be seen more as a ceiling, while support for Mr. Kerry, the lesser-known challenger, is more like a floor.
http://www.nytimes.com/2004/04/23/opinion/23LIZZ.html