(CNSNews.com) - Louis Fisher, a scholar in residence at the Constitution Project who served for 40 years as a constitutional law expert at the Library of Congress, says Americans and members of Congress should understand that President Barack Obama committed a “very grave offense” against the Constitution in taking military action in Libya without congressional authorization.

“I am not going to recommend that the House Judiciary Committee hold impeachment hearings, but I would like members of Congress and the public to say that nothing would be more impeachable than a President who takes the country to war without coming to Congress, who does it unilaterally,” Fisher told CNSNews.com’s Online With Terry Jeffrey.

“So, I would like people to be educated, including members of Congress, to be educated that that is a very grave offense,” said Fisher.

On March 19, President Barack Obama ordered the U.S. military to take actions against the Libyan regime of Muammar Gadhafi.

The day before that, Obama had given a speech stating that a resolution passed by the U.N. Security Council on the previous day that authorized the use of military force in Libya would justify U.S. action there.

“Yesterday, in response to a call for action by the Libyan people and the Arab League, the U.N. Security Council passed a strong resolution that demands an end to the violence against citizens,” said Obama. “It authorizes the use of force with an explicit commitment to pursue all necessary measures to stop the killing, to include the enforcement of a no-fly zone over Libya.”

In his March 19 speech informing the American people that he had ordered military action in Libya that was already taking place as he spoke, Obama said he was taking the action to defend the “writ of the international community.”

“So we must be clear: Actions have consequences, and the writ of the international community must be enforced,” said Obama. “That is the cause of this coalition.”

Fisher, whose book Presidential War Power is a definitive scholarly account of the drafting of the constitutional war power and its historical interpretation and implementation, scoffs at Obama’s argument that the United Nations, which the U.S. joined through a treaty ratified by the Senate, can usurp the war power the Constitution gives to both houses of Congress.

“He said I have authorization from the Security Council. It is not authorization under U.S. constitutional law,” said Fisher.

“First of all, I would like to make it clear that in the U.N. Charter, you cannot have the president and the Senate through the treaty process--the UN Charter or NATO--you cannot have those two actors take the power of Congress and the House of Representatives and give it to either the Security Council or to NATO countries,” said Fisher.

“And I think even people who read presidential power broadly know that that is not possible,” he said.

“You cannot use a treaty to amend the Constitution,” he explained.

In Presidential War Powers, Fisher recounts how Framers James Madison and Elbridge Gerry introduced an amendment at the Constitutional Convention to change the language of the proposed power to make war. The draft presented to the full convention said Congress would have the power to “make” war.

“Mr. Madison and Mr Gerry moved to insert ‘declare,’ striking out ‘make’ war; leaving to the Executive the power to repel sudden attacks,” wrote Madison in his notes from the convention.

Explaining this proposed change, Gerry said he “never expected to hear in a republic a motion to empower the Executive alone to declare war.”

Madison and Gerry’s amendment was accepted by the convention and included in the Constitution ratified by the states. Had Madison and Gerry’s amendment not been accepted, the Constitution would have given Congress all power over war by giving Congress alone the power to "make" war. With the amendment, as per Madison’s notes, Congress still had the power over war except when the president needed to “repel sudden attacks.”

Fisher writes in is book, and said in his interview with CNSNews.com, that all presidents from George Washington through Franklin Roosevelt respected this understanding of the Constitution until President Harry Truman sent U.S. troops into Korea without authorization from Congress--using a U.N. resolution as his justification.