It's not unusual for Americans to criticize the wars their country is fighting. But it is pretty unusual for an army officer to speak out against the legality of the war in which he is actively serving.

Army Capt. Nathan Michael Smith is doing just that. In fact, last week, the 28-year-old officer filed a lawsuit against President Barack Obama himself, challenging the legal authorization for the war against the so-called Islamic State.

Capt. Smith is an intelligence officer stationed in Kuwait, as part of the fight against ISIS. He says the war against ISIS is a just war. But he has a problem.

“My conscience bothered me,” Smith says in his complaint. “When I was commissioned by President Obama in May 2010, I took an oath to ‘preserve, protect and defend the Constitution of the United States.’ The Constitution gives Congress the power to declare war, and the War Powers Resolution prohibits the president from waging war without a declaration of war or specific statutory authorization. How could I honor my oath when I am fighting a war, even a good war, that the Constitution does not allow, or Congress has not approved?”

“To honor my oath,” the complaint continues, “I am asking the court to tell the president that he must get proper authority from Congress under the War Powers Resolution, to wage the war against ISIS in Iraq and Syria.”

The War Powers Resolution was passed in 1973, over a presidential veto, in the aftermath of the Vietnam War and its unauthorized extensions into Laos and Cambodia.

“Senators said we cannot allow this to happen again,” according to Bruce Ackerman, the constitutional consultant for Smith’s legal team. He's a professor of law and political science at Yale Law School.

The Obama administration argues that the military action against ISIS is legal under the authority granted by Congress in 2001 after the 9/11 attack. That authorizes the president “to use all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons.”

Ackerman asks how the authorization for a war against al-Qaeda in Afghanistan can justify “a completely different war against the Islamic State?” He points out that ISIS has repudiated al-Qaeda and al-Qaeda has repudiated ISIS.

However, the administration’s supporters say that ISIS is an off-shoot of al-Qaeda, with similar goals of attacking the US and its interests.

Supporters of the war on ISIS also say that Congress has implicitly authorized the campaign, by repeatedly authorizing appropriations to fund operations against ISIS. Ackerman says the court will have to hear the arguments to decide the issue. But he says many constitutional experts, himself included, find the administration’s case not to be credible.

According to the New York Times, the administration did consider seeking new authorization after ISIS swept through Syria and Iraq in the summer of 2014. But it was thought politically impractical at the time, given the dysfunction in the Republican-controlled House of Representatives. Obama decided the situation called for immediate action, according to the Times.

Under the War Powers Resolution, the president can respond to threats with military action for 60 days, during which time he is supposed to obtain the approval of Congress. If he fails to get that support, he must withdraw troops and end hostilities within 30 days.

The bottom line, Ackerman says, is the future safety of the United States. “I am defending the Constitution of the United States.”

“If President Obama’s precedent is allowed to stand,” says Ackerman, “it will provide an authority for the next president, and the president after that, to declare a war on the basis of a 20-, 30-year-old resolution anywhere in the world, on the ground there is some connection with the original al-Qaeda.”

“This,” argues Ackerman, “would be a very serious, and in my understanding, deeply unconstitutional, transformation in American government.”

“We need fundamental constraints on presidential power to declare war,” he concludes.   

From PRI's The World ©2016 PRI