From a long San Francisco Chronicle article about Pat Tillman's life and death:

Baer, who served with Tillman for more than a year in Iraq and Afghanistan, told one anecdote that took place during the March 2003 invasion as the Rangers moved up through southern Iraq.

“I can see it like a movie screen,” Baer said. “We were outside of (a city in southern Iraq) watching as bombs were dropping on the town. We were at an old air base, me, Kevin and Pat, we weren’t in the fight right then. We were talking. And Pat said, ‘You know, this war is so f— illegal.’ And we all said, ‘Yeah.’ That’s who he was. He totally was against Bush.”