U.S. President Barack Obama leaves with Vice President Joe Biden after delivering remarks on his management agenda in the State Dining room of the White House in Washington, July 8, 2013.

President Obama and Vice President Biden once held radically different views on the use of military force without congressional authorization. During the 2008 presidential campaign, both made undeniably clear the president could not authorize a military strike without congressional except for a case of an "imminent threat." Then-Senator Biden found the offense impeachable.

"I want to make it clear to you," Biden said speaking at a campaign event in Davenport, Iowa, in December 2007. "I've drafted, with the help of 17 years I was the chairman of the Judiciary Committee or the ranking member. Ladies and gentlemen, I drafted an outline of what I think the constitutional limits have on the president in over the war clause. I went to five leading scholars, constitutional scholars, and they drafted a treatise for me, and it's being distributed to every senator. And I want to make it clear and I made it clear to the president, if he takes this nation to war in Iran, without congressional approval — I will make it my business to impeach him."

Biden reiterated the claim in his "on the issues" page on his former campaign website, saying the nation could only be taken to military action with the approval of Congress expect to stop an "imminent attack" on the United States.

It is precisely because the consequences of war – intended or otherwise – can be so profound and complicated that our Founding Fathers vested in Congress, not the President, the power to initiate war, except to repel an imminent attack on the United States or its citizens. They reasoned that requiring the President to come to Congress first would slow things down… allow for more careful decision making before sending Americans to fight and die… and ensure broader public support.



The Founding Fathers were, as in most things, profoundly right. That's why I want to be very clear: if the President takes us to war with Iran without Congressional approval, I will call for his impeachment.



I do not say this lightly or to be provocative. I am dead serious. I have chaired the Senate Judiciary Committee. I still teach constitutional law. I've consulted with some of our leading constitutional scholars. The Constitution is clear. And so am I.



I'm saying this now to put the administration on notice and hopefully to deter the President from taking unilateral action in the last year of his administration. If war is warranted with a nation of 70 million people, it warrants coming to Congress and the American people first.

Then-Senator Obama likewise agreed with the assessment from Biden saying the president of the United States could only authorize an attack in the instance of "imminent threat" to the nation, responding to a question to a 2008 Boston Globe questionnaire on executive authority.

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.



As Commander-in-Chief, the President does have a duty to protect and defend the United States. In instances of self-defense, the President would be within his constitutional authority to act before advising Congress or seeking its consent. History has shown us time and again, however, that military action is most successful when it is authorized and supported by the Legislative branch. It is always preferable to have the informed consent of Congress prior to any military action.



As for the specific question about bombing suspected nuclear sites, I recently introduced S.J. Res. 23, which states in part that "any offensive military action taken by the United States against Iran must be explicitly authorized by Congress." The recent NIE tells us that Iran in 2003 halted its effort to design a nuclear weapon. While this does not mean that Iran is no longer a threat to the United States or its allies, it does give us time to conduct aggressive and principled personal diplomacy aimed at preventing Iran from developing nuclear weapons.

The White House is currently weighing a response to Syria's use of chemical weapons.

A video of Biden's Iowa remarks has been embedded below: