I don't think she made a mistake in voting for the Iraq War given the information the Bush administration had provided to Congress using Colin Powell and other trusted officials as puppets. She did make a mistake not giving credence to dissenting opinions, not immediately distancing herself from the vote the moment it became clear there were no WMDs in Iraq, and in not making her decision-making process more transparent.
As much as Democrats want to eat their own for voting "yes" on Iraq. The ultimate responsibility lies with Dick Cheney and the Department of Defense for cherry-picking poor evidence to support their already-chosen line that Saddam was developing WMDs. To suggest anything else is to distract from the main instigators who still have yet to be held accountable.
No, every member of Congress that voted for the authoritation shares the responsibility. That goes for Hillary, as well as Biden or Kerry.
And I have a very hard time believing she was stupid enough to actually believe all that crap. Whatever one may say about Hillary, she's certainly not stupid. She's just a politician: it was purely opportunistic vote for something that was "popular" back then.
Look, I can understand argument that it was a mistake, but not an irredeemable mistake. After all, every single member of Congress in 1964 (except for Wayne Morse and Ernest Gruening) voted for the Gulf of Tonkin resolution, but most eventually corrected their ways. But it was still a big mistake and those who voted for the resolution shares some responsibility.
I agree that they share some responsibility, and I agree that Hillary is absolutely a politician who was considering how the vote would "look" when she made it. I disagree with the implication that she didn't actually believe there was evidence of WMDs and voted for the resolution anyway because of popular opinion. Nobody no matter how bitterly partisan would vote to support a war if they legitimately thought the whole justification was completely made up unless they had some other reason to support the war cough*oil*cough and I don't think Hillary did at the time.