President Obama is taking a calculated gamble in seeking congressional backing before launching a military strike at Syria to degrade the Assad regime's ability to launch further chemical strikes against its people. His calculations in this case are the right ones.

In making the case for military action to Congress, the administration will also be presenting its arguments to the American people. If the president is successful, U.S. actions against Syria will carry greater weight on the international stage for his having used the democratic process to build consensus.

On the domestic side, the public will at least have a greater understanding of the decision to act and its implications than would have been the case had President Obama used his executive authority to act quickly and independently, presenting his arguments subsequently.

The discussion with Congress is also engaging a broader discussion on a Syrian strategy - which up to now has been sorely lacking - with the expectation of achieving President Obama's stated goal of reaching a negotiated political settlement that removes Syrian President Bashar Assad from power and ends the fighting.

Tired of expending U.S. blood and wealth in Iraq and Afghanistan, many question why it should be this nation's concern if a Middle Eastern tyrant should choose to unleash chemical weapons on his own people - on Aug. 21 killing about 1,500, many of them sleeping children, when the missile shells with Sarin gas landed at 2 a.m. in a rebel-friendly Damascus suburb.

But those who would turn a blind eye must accept that the message Mr. Assad would receive from inaction is that chemical weapons remain an option as he seeks to suppress the rebellion. And, in failing to act on Mr. Assad's crossing of President Obama's red line, what credibility would the United States have when it states that a nuclear-armed Iran is unacceptable?

After flawed intelligence and manipulated information about the immediate threat of weapons of mass destruction led to the invasion of Iraq (there were no WMDs and no immediate threat), skepticism about the reports of chemical attacks in Syria is understandable. But, unlike Iraq, evidence grows that the chemical weapons were used by the Assad forces. Another advantage of the congressional debate is more time for that evidence to be presented and vetted.

As for the nature of any U.S. military action, as President Obama states, "This is not Iraq, and this is not Afghanistan." Under discussion is a limited campaign, likely using cruise missiles to target the dictator's command and control structures, damage military facilities used in delivering chemical attacks and potentially destroying his palaces.

The intent is to change Mr. Assad's calculation, making the cost of utilizing chemical weapons much higher than employing them.

It is not without risk. Syria, Iran or their mutual non-state ally, Hezbollah, could lash out at third-party states, daring the United States to escalate. But the risk of doing nothing and inviting future recklessness by these regimes is greater.

There are also indications that the administration is considering increased U.S. support for the Free Syrian Army, seen as the moderate option among the rebel forces aligned against Mr. Assad. Fear has grown that al-Qaida sympathizers and other jihadists, aligned with the Ahrar al-Sham Brigade, have gained the upper hand among rebel forces and any arms supplied to support the rebellion could fall into their hands.

In a recent commentary in the Wall Street Journal, however, Elizabeth O'Bagy, a senior analyst at the Institute for the Study of War, who has spent hundreds of hours on the ground with rebel groups, reports that moderate, pro-democracy forces remain viable and in control of large swaths of the divided nation. They should receive greater U.S. support if the goal is to strive towards an eventual outcome in Syria that aligns with U.S. interests in the Middle East.

President Obama faces a tough selling job. He should consider a prime-time address to the American people. His credibility and that of the nation are on the line.