Resolute leadership, clear goals and as much unity in Washington as possible are required when America contemplates military action. Someone should let the White House know.
Two years ago President Obama said that "the time has come" for Syrian President Bashar Assad "to step aside." Apparently he was just thinking out loud. He offered no way to make that happen.
A year ago, Mr. Obama said any Syrian use of chemical weapons would be "a red line" leading to "enormous consequences." Assad crossed the red line earlier this year. Nothing happened. He used chemical weapons again late last month, killing an estimated 1,400 men, women and children.
On Wednesday, Mr. Obama insisted, "I didn't set a red line." Instead, he claimed, "the world set a red line." He also said: "My credibility isn't on the line. The whole international community's credibility is on the line."
Yet the international community shows little inclination to act. In part, that's because Mr. Obama has taken "leading from behind" to the extreme by letting British Prime Minister David Cameron go first in asking for parliamentary approval for a strike on Syria. When the British Parliament refused, Mr. Obama's aides let the New York Times know that "Mr. Cameron had mishandled the situation."
A week ago, Mr. Obama was ready to bypass lawmakers and order a military strike. Then he suddenly reversed his position, announcing that he would ask Congress for authorization to use force.
Meanwhile, some of his closest advisers are treating the legislative branch as a collection of nitwits. Mr. Obama's former senior adviser, David Axelrod, tweeted that "Congress is now the dog that caught the car." An unnamed White House aide told the Washington Post, "We don't want them [Congress] to have their cake and eat it, too."
This is a peculiar way to obtain congressional backing for a strike in Syria. Mocking senators and congressmen won't convince them that America's credibility will be badly damaged—with potentially grave consequences for U.S. allies and interests—if they withhold approval.
To win over understandably skeptical lawmakers, the president must convince them that America has vital national security interests in Syria. If Assad stays in power, it will be a victory for Hezbollah, Iran and Russia, tilting the balance in the Middle East.
He must also reassure members that things are likely to get better, not worse, if the Syrian dictator falls. While Mr. Obama cannot guarantee the outcome, he must argue it is unlikely that al Qaeda Islamists will replace Assad. That case can be made.
Most in the Syrian opposition aren't jihadists. It's true that the al Qaeda element is better trained and armed than the moderates, but the Syrian people will not tolerate a government led by a terrorist movement dominated by foreign fighters. More significantly, if the U.S., Saudi Arabia, Turkey and others strengthen the non-Islamist rebels, a better outcome is possible.
Opposition in Congress to an authorization for the use of force will be fierce among Democratic and Republican anti-interventionists. Mr. Obama must move some Democrats in this camp by personal suasion and appeals to party loyalty. There is no chance that GOP neo-isolationalists will support him.
Other Republicans will be tempted to oppose Mr. Obama out of a sense of the public's war weariness and a belief that the president's approval ratings will suffer if he strikes Syria. The GOP should reject this political calculus.
It's true that when asked in an NBC poll late last month if the U.S. should take military action, provide weapons to the Syrian opposition or give humanitarian assistance, only 26% of respondents chose the military option. But 42% of Americans said they believe the U.S. should take military action in response to the use of chemical weapons, while 50% don't.
If told such a response would be "limited to using cruise missiles" in order "to destroy military units and infrastructure" used in the chemical attacks, the numbers shift to 50% support and 44% opposed. Framed as a general principle—that "the use of chemical weapons is a 'red line' " that "would require a significant U.S. response, including the possibility of military action," 58% agree while 35% disagree.
The bottom line is that Americans are not eager for military action in Syria. Presidential ambivalence won't convince the public they should care what happens there. But it isn't too late. Mr. Obama can bend opinion and the will of Congress his way. It won't be easy. For the sake of America's national security, I hope he succeeds.
A version of this article appeared September 5, 2013, in the U.S. edition of The Wall Street Journal, with the headline: How Not to Persuade Congress on Syria and online at WSJ.com.