Given the mood of the country after 9/11 Democrats could scarcely have refuse a request from the president telling us how much peril we were in. Now we know it was a snow job. The CIA doubted the WMD evidence and furthermore, we had considerable control of Iraq at that time due to the UN sanctions- we controlled Iraq's boarders and air space and UN inspectors were there in Iraq checking for WMD (and finding none) so I think this could have been handled in a much more peaceful way but Bush and Cheney were so gun-ho for war nothing would stop them.
In any case, I think the Iraq war is the worse blunder this country has ever made. It has cost us dearly in dollars and lives and tarnished our image around the world- and rather than make us safer it has only encouraged even more Islamic hatred towards us.
As for the Democrat's part in the economic problems- yes- their desire for more lenient mortgage rules played a part- but at least their intention was good- to help people of modest means buy a home- which is more noble than helping rich businessmen get even richer as so much of the Republicans deregulation did.