Barack Obama on presidential war-making power, in 2007:
The President does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation.
Barack Obama on presidential war-making power, in 2011:
UPDATE: John Larson’s (D-CT) complaint seems fair:
They consulted the Arab League. They consulted the United Nations. They did not consult the United States Congress.