The resolution was drafted in response to an amendment passed in the senate in September of 2007 which designated Iran's Revolutionary Guard as a terrorist organization. Obama argued that the amendment could be used by President Bush to justify war with Iran.
Joe Biden's spokeswoman, Elizabeth Alexander, said at the time that Mr. Biden also believed the amendment could be used to justify military action against Iran.
The spokeswoman added, "[Sen. Biden] has also made clear many times his view that the president lacks the authority to use force against Iran absent authorization from Congress."
Here's a small snippet of Obama's 2007 Senate resolution:
Mr. REID (for Mr. OBAMA) introduced the following joint resolution; which was read twice and referred to the Committee on Foreign Relations...It should also be noted that while Obama asserted in a 2007 interview that "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," he stipulated that "the President does have a duty to protect and defend the United States" and that "in instances of self-defense, the President would be within his constitutional authority to act" unilaterally.
Whereas any offensive military action taken by the United States against Iran must be explicitly authorized by Congress: Now, therefore, be it Resolved by the Senate and House of Representatives of the United States of America in Congress assembled, that nothing in the... resolution [amendment] previously adopted, or any other provision of law.. shall be construed to authorize, encourage, or in any way address the use of the Armed Forces of the United States against Iran.
Since Iran is arming and training Iraqi and Afghan insurgents to murder U.S. troops abroad, an attack against Iran, clearly, can be construed as an act of self-defense. Bombing Iran's nuclear facilities can also be defined as such, especially if and when Iran reaches the threshold of nuclear weapons capability - if it hasn't already reached that point.
Conversely, attacking the Libyan regime is clearly not an act of self-defense, even if this was the case in the days of yesteryear.
This is not to suggest that Gaddafi is a kind-hearted and benevolent man, who is undeserving of punitive measures, nor is this an attempt to address the question as to whether the U.S. should or should not be bombing Libya. The point being made is that the President should have obtained congressional authorization before launching attacks on Libya, if he wished to abide by his own resolution and previous statements.
If the President, however, wished nothing more than to remain true to his hypocritical, flip-flopping ways, then the path he chose was undoubtedly the correct one.
Related Video: Obama to Bush: You do not have congressional authorization to attack Iran