Ten years ago, the president of the United States stood before the world and said that the use of chemical weapons and the threat of weapons of mass destruction demanded military intervention in Iraq.

Secretary of State Colin Powell made the case for war on Feb. 3, 2003 when he told the United Nations that the Iraqis had collected four tons of VX nerve gas, 25,000 liters of anthrax and 65 facilities that housed chemical weapons.

The only problem was it wasn't true.

And now, despite the hard and costly lessons of that errant Mideast campaign, it appears the United States is walking down that path again.

The White House has made clear that it is planning a military strike to punish the Syrian government for allegedly using chemical weapons against civilians. The used of such weapons of mass destruction cannot go unpunished, he contends.

The evidence, President Barack Obama says, is incontrovertible that Syrian President Bashar al-Assad's military carried out a deadly chemical weapons attack on civilians on Aug. 21. At the same time, he did not present direct evidence to support that contention.

There appears to be little doubt that an attack did take place, one that has resulted in the deaths of hundreds. But the possibility remains, no matter how remote, that it may have been carried out by another interest, a terrorist group or by a rogue element within Syria's strained military.

U.N. investigators, who continue to collect blood and urine samples from the victims and conduct investigations in one of the areas of the attack, say it is not yet clear to them who was responsible. For that reason, U.N. chief Ban Ki-moon continues to plead for more time and for more diplomacy before resorting to a military strike.

That's one of the reasons why British lawmakers handed Prime Minister David Cameron a stunning defeat Thursday in rejecting his bid to join the U.S. in its military plans.

Unfortunately, Obama administration officials made clear Thursday that they were ready to go it alone.

A unilateral U.S. military response would be a mistake.

Chemical weapons are, as Secretary of State John Kerry said, a "moral obscenity," and President Obama was right in making clear that the use of them would cross a "red line."

There's legitimate concern that if Assad does not experience the world's wrath for crossing this ethical line of warfare, that it could invite others to resort to similar tactics.

A world response is demanded. But the president should resist being goaded by the hawks who appear convinced that the only meaningful message is one from the Pentagon. Meanwhile, Obama also seems to be getting pressure from those on the left who believe that a surgical humanitarian strike against the immorality of chemical weapon use is somehow achievable.

As it is, Israeli citizens are stocking up on gas masks and other supplies in anticipation of the potential chain reaction of events — from Damascus, Iran, Hezbollah or elsewhere — that is likely to ensue.

If history has shown anything it's that missile strikes rarely provide moral clarity. The U.S. has made enough Mideast mistakes. Let's not make another.