No, don't vote for Nader or you will no doubt see Bush in office for another four years.
There is no way to defend Kerry, really. For some things, yes. I'm sure he did expect Bush to take things a bit more seriously before deciding to bomb Iraq; just because he voted to give him the authority does not mean he expected Bush to take the brute force approach to the war. Then again, at some points he did sound like he was pretty impatient.
That being said, it still doesn't make up for all of his other contradictions. Should this advertisment ever become popular, this could seriously put an end to Kerry's chance to become President. If this is played at the Republican National Convention, he's really screwed. Understand that people can change their mind; perhaps Kerry did not realize what he was saying until he saw the aftermath, and would hate to admit he made a mistake in judgement (especially BEFORE possibly being accepted into the White House after the election.)
As for things he voted for in the early/mid 90's, that was a TOTALLY different time, and there's no need to hold that against him. In the mid 90's almost everyone thought Iraq and WMD's that Saddam may have are a threat, even the international community. I remember reading a newspaper article in the Pittsburgh Post-Gazette that quoted almost every significant European country saying they'd support Clinton if he decided to go to war with Iraq.
What pisses me off is how the media kind of picked off all of the other candidates and put the spotlight on Kerry, I mean no one else even had a chance after that... really stupid. I agree, he's the lesser of two evils, but this video still proves him to be a contradicting son of a bitch regardless. He's still getting my vote, but I can't say that I 100% trust this man. Of course, I'd still trust him more than I would George Bush, quite possibly one of the biggest liars in the history of United States Presidents.
Interesting, very interesting. Like I said, this video could ruin Kerry.