REASONS WHY THEY ARE AGAINST THE LIBERATION OF IRAQ
Democrats, especially those who voted to authorize any military action the President deemed necessary, are having a particularly difficult time coming up with the reason they oppose(d) the war. Their reasons have evolved over time, and bear no relation to any facts available in 2002, when war was authorized by Congress. Here's their anti-war evolution.

First, Dems supported military action by passing the resolution authorizing the use of force.

Then, they said they didn't mean to vote for it, we shouldn't go unless the U.N. says (again) it's OK.

Then, when most of the Security Council said OK, they said we shouldn't go because France didn't say OK.

Then, when we found out that maybe Saddam wasn't getting uranium from Africa, they said we shouldn't have gone because they only voted for the resolution because Bush said Saddam was getting uranium from Africa.

Then, they realized Bush didn't say this (if at all) until after the vote, so they said they opposed the war because it was almost summertime.

Then, they argued that it was too dangerous to go to war because Saddam would surely use chemical and biological weapons.

Then, they argued it was too dangerous because we might actually destroy some chemical and bio weapons and release them into the air, just like we did in 1991, causing Gulf War Syndrome.

Then, they opposed the war because we didn't win in 1 week.

Then, they opposed the war because we didn't win in 2 weeks.

Then, they opposed the war because we won in 3 weeks, which proved that Iraq wasn't really dangerous.

Then, they opposed the war because it didn't take 3 days to reestablish stability and security in Baghdad.

Then, they opposed the war because Saddam escaped and was leading a resistance.

Then, they opposed the war because we didn't have a plan for capturing Saddam.

Then, we captured Saddam and they opposed the war because Saddam wasn't really dangerous anyway and we weren't any better off having caught him.

Then, they opposed the war because David Kay only found weapons labs and illegal missiles but no actual WMDs.

Explaining why John Kerry is against the war may be more simple than all that. Because Bush is for it. Although, it could be because he thinks that the United Nations should control our military. In 1970, he said:

I'm an internationalist. I'd like to see our troops dispersed through the world only at the directive of the United Nations.

Since he once argued that we shouldn't go to war in Iraq (he didn't seem to think this way about Serbia) without the approval of France and Russia, perhaps he still thinks this way. Sounds like a job for Tim Russert.