I thought the UK Parliament debate was constructive.   Some other commentaries I found constructive linked to here.

Sen. McCain made legitimate points in favor of an intervention during an NPR interview this morning.

Roger Cohen also made legitimate points in favor of intervention in the today’s NY Times, Red Lines Matter (emphasis added):

Europe knows, and [Berlin] in particular, about the importance of American “red lines.” West Berlin, caught for more than four decades 100 miles within the Soviet occupation zone, survived on the credibility of the U.S. commitment to it, demonstrated by the Allied airlift in response to the Soviet blockade of 1948.

A shattered Europe became whole, free and prosperous under the shield of U.S. credibility. Article 5 of the North Atlantic Treaty spelled out that an armed attack against one member “shall be considered an attack against them all.” This was believable enough to deter a Soviet attack on Western Europe… It is the credibility of the United States as a European and Asian and Middle Eastern power that underwrites global security…

Syria, in the words of Secretary of State John Kerry, speaking of the chemical attack, has become a “moral obscenity.” The man bearing ultimate responsibility for that obscenity is Assad.

Values cannot be all of foreign policy; perhaps they cannot even be a quarter of it; but a U.S. foreign policy stripped entirely of values is no longer American. U.S. authority is tied to its moral stature as a state of laws committed to freedom. It is equally tied to the credibility of its word. In Syria the two inextricable strands of U.S. foreign policy — values and realpolitik — have come together.

That is the kernel of the matter now before Congress. As Senator John McCain has said, a no vote in Congress on a U.S. military riposte to the chemical weapons attack would be “catastrophic” for the United States and its credibility in the world. If Assad can thumb his nose at America anyone can, including the Islamic Republic of Iran.

My initial response to Obama’s decision to seek congressional support and to the long delay involved was that it betrayed a by-now familiar hesitancy. I have reconsidered: This is a necessary post-9/11 rebalancing from the dangerous “unbound powers” of the presidency of which Obama has spoken, powers that opened the way to the compromising of America’s “basic values” to which he also alluded this year.

American interests and values are aligned in requiring that Assad answer for his acts. Because Syrian diplomacy is now backed for the first time by the credible threat of force, it may even produce something over the next 10 days.

But I doubt it. In that case, Congress must assume its responsibilities.

Three days into the Cuban missile crisis, Gen. Curtis LeMay of the U.S. Air Force suggested the president’s refusal to order immediate air strikes on the Soviet missiles was “almost as bad as the appeasement at Munich.” He had mistaken Kennedy’s deliberation for indecision. The U.S. red line was upheld — as it must be in Syria today.

McCain’s and Cohen’s arguments in favor of intervention are valid.  So are the arguments against.  I think Syria is a no win situation.  No matter what actions are taken or not taken there will be negative consequences and plenty of opportunity to second-guess.