Barack Obama was not a member of the US Senate at the time. Thus he did not vote on the invasion. But as a member of the state senate in Illinois, he expressed his vocal opposition, calling it a foolish decision by President Bush; and when he joined the U.S. senate in 2004, he voted against the surge and against additional funding for expanding the war. In 2008, as a candidate, he promised he would end our involvement in Iraq if he were elected, and that is exactly what he did.