You're putting a fair bit of energy into comparing this election against past elections, and trying to match patterns, like "bumps" at expected times like vice presidential selection and the conventions. But you want to be careful about relying too much on the past as a predictor of the future. A lot of things are different now. One change is emotional in character: It's been a long time since an election seemed to have so much to do with exterior reality instead of contrived and abstract ideological differences between the two parties. The 2000 election was all about how-many-angles-can-dance-on-the-head-of-a-pin theological issues like Social Security and education funding, and tax policy. In 2004 there are monsters under the bed and barbarians at the gate--butterflies in the stomach, not calculation in the brain, will decide this election.

A better way to phrase Kerry's nuclear question might be: "Are you feeling better now than four years ago?", and the answer would obviously be a resounding "No!". Bush is in the position of defending his job performance with negative hypotheticals: "Things could have been worse, so I must be doing a good job. I thwarted a lot of terrorist attacks, but I can't tell you about it to protect our sources, so you'll just have to take my word for it. Iraq would be much worse off now if Saddam was still running things. And the economy could be worse too, why the blah indicator was down 3 more points during the blahblah recession than it is now. And I tell you, things will definitely be worse under that Kerry fella...". Zzzzzzz...

My point is that this election will be decided more by emotional factors than by arguments based on statistics or hypothetical worse-case scenarios. Has Bush's job performance given a majority of Americans a warm-and-fuzzy feeling that our country and our lives are in good hands? You know that a lot of people have already said no, and on Election Day lingering doubt will emerge to influence a lot of the presently-undecided voters. The burden of proof is on Bush to clearly demonstrate that he should be retained in office; doubt will sink him otherwise.

For Bush, the goal isn't to win the election, the goal is to not lose it.