Robert Gates:

I've just reassured myself of this, and he assured me that in fact that his statements, prior to him taking this office, in which he advocated the ouster of Saddam Hussein still stand. Now, keep in mind that the secretary believed that the ouster of Saddam Hussein -- that the goal here was not to necessarily -- liberating Iraq was a by-product of the goal. The secretary believed that Saddam Hussein was a destabilizing influence in the region who was intent, if he didn't them already, on developing weapons of mass destruction. He was convinced, the secretary was, that the sanctions were crumbling and that it was only a matter of time before -- if he didn't have them already, he would develop a weapons of mass destruction program. In light of that, he believed and still does believe that the right course of action was to topple Saddam Hussein.
- Pentagon Press Secretary Geoff Morrell, September 20, 2007

"I think we clearly have to keep the pressure on terrorism globally. This doesn't end with Afghanistan by any imagination. And I think the president has made that clear. I think we have made that clear. Terrorism is a global menace. It's a scourge. And it is absolutely vital that we continue against, for instance, Saddam Hussein."
- John Kerry, December 14, 2001

"I will be voting to give the President of the United States the authority to use force, if necessary, to disarm Saddam Hussein because I believe that a deadly arsenal of weapons of mass destruction in his hands is a real and grave threat to our security."
- John Kerry, October 9, 2002

"Without question, we need to disarm Saddam Hussein. He is a brutal, murderous dictator; leading an oppressive regime he presents a particularly grievous threat because he is so consistently prone to miscalculation. So the threat of Saddam Hussein with weapons of mass destruction is real."
- John Kerry, January 23, 2003

John Kerry also voted to authorize the use of force against Iraq.

Christopher Dodd:

Christopher Dodd voted to authorize the use of force against Iraq.

Bill Richardson:

Bill Richardson apparently supported Bush's decision to go to war.

Richard Holbrooke:

"Iraq will be one of the major issues facing the incoming Bush administration at the United Nations."

…

"Saddam Hussein's activities continue to be unacceptable and, in my view, dangerous to the region and, indeed, to the world, not only because he possesses the potential for weapons of mass destruction but because of the very nature of his regime. His willingness to be cruel internally is not unique in the world, but the combination of that and his willingness to export his problems makes him a clear and present danger at all times."
- Richard Holbrook, January 11, 2001

"On the issue of American objectives, this administration has (rightly) called for regime change. Unfortunately, few other nations in the world, and especially in the region, will openly subscribe to such a goal. Other nations will probably seek to limit any resolution to the issue of weapons of mass destruction. This, however, is less of a problem than it initially appears. If military action begins, it will soon become evident that it is impossible to eliminate the weapons without a change in regime."

"Given that the Iraqi military is only one-third the size it was before the Gulf war, and American forces far stronger, the odds favour an American success. But no one can foresee clearly what will occur once a war starts. Will there be an assassination, a rebellion, a crumbling of the Iraqi military, a quick victory that pre-empts Iraqi missile attacks on Israel, a protracted struggle, or something worse? Whatever happens, once launched, the effort against Saddam cannot be stopped until its goal is achieved and the overwhelming power of the US has prevailed."
- Richard Holbrooke, August 29, 2002

Joe Biden:

Joe Biden voted to authorize the use of force against Iraq.

It appears that Obama's likely foreign policy team was universally in favour of the Iraq War to some degree. I'm not sure what exactly this indicates about Obama. Certainly there's been some in consistency in his position over the past two years.