Associated Press
President Barack Obama meets with his national security staff to discuss the situation in Syria.

I have not had a classified briefing on the situation in Syria; all I know is what I read in the media. However, it is clear that Syria is embroiled in a full-scale civil war.

During the Senate debate over possible American intervention in Kosovo, one foreign policy expert set forth three fundamental rules regarding other nations' civil wars. (1) Stay out, if you can. (2) If you can't, then pick a side. (3) Make sure your side wins.

Because of humanitarian concerns about Syria, we are moving past Rule 1, "Stay out." Assad is an iron-fisted dictator who has brutally suppressed his population and there is mounting evidence that he has used poison gas against them. However, Rule 2, "Pick a side," is not as easy a call as it may seem.

We certainly want Assad gone, but we also know that many in the rebel movement against him are terrorists with ties to al-Qaida. Once in power, they could well produce a human rights record as bad as Assad's. Further, a "surgical" military strike by the U.S. could push Russia closer to both Assad and Iran, helping that nation move closer to obtaining a nuclear weapon. President Obama's tentativeness on Rule 3, "Make sure your side wins," has made us look weak but is understandable.

However, given his previous statements on the subject, information about Assad's use of poison gas now forces Obama to make a clear decision. Should he order a "shot across the bow" and possibly trigger events that would make things worse (not to mention kill tens of thousands of innocent Syrian civilians)? Or should he continue to temporize and possibly damage American credibility in a way that would also make things worse (in the rest of the world as well as the Middle East)? That is an oversimplification of his options, but it illustrates that there are no good ones.

One thing is sure. The Constitution gives Congress the power to declare war. The exact way in which that is done may differ from one situation to the next, but the requirement that Congress give its approval before major military action takes place is very clear. If President Obama decides to take such action in Syria, he should obtain congressional authorization before he does it.

George H. W. Bush did not embark on the first Gulf War without congressional approval. Bill Clinton did not begin bombing in either Kosovo or Iraq without congressional approval. George W. Bush was told by his lawyers that he could proceed in Iraq based on the permission given Clinton but still went to Congress for a fresh, specific grant of authority — which he got, with support from then Senators Hillary Clinton, John Kerry and Joe Biden.

Obama's rhetoric about the need to take action in Syria has put him in a difficult position; further hesitation in the light of the new evidence would be a humiliating climbdown for a president who set out to increase world respect for America. It would also be a significant propaganda victory for Assad. But making the case for action would not be easy. The U.N. Security Council, which voted 15-0 for action in Iraq, has said no to a strike in Syria, as has the British Parliament, which also authorized action in Iraq. If we act, we will act alone.

When faced with similar tough situations, Obama's immediate predecessors went to the Congress for support, and got it. Before committing America to military action in Syria, Obama must do the same. The Constitution requires it and the people deserve no less.

Robert Bennett, former U.S. senator from Utah, is a part-time teacher, researcher and lecturer at the University of Utah's Hinckley Institute of Politics.