Half a century ago, at the height of anti-Communist fervor, Congress added the words ''under God'' to the Pledge of Allegiance. It was a petty attempt to link patriotism with religious piety, to distinguish us from the godless Soviets. But after millions of repetitions over the years, the phrase has become part of the backdrop of American life, just like the words ''In God We Trust'' on our coins and ''God bless America'' uttered by presidents at the end of important speeches.

Yesterday, the United States Court of Appeals for the Ninth Circuit in California ruled 2 to 1 that those words in the pledge violate the First Amendment, which says that ''Congress shall make no law respecting an establishment of religion.'' The majority sided with Michael Newdow, who had complained that his daughter is injured when forced to listen to public school teachers lead students daily in a pledge that includes the assertion that there is a God.

This is a well-meaning ruling, but it lacks common sense. A generic two-word reference to God tucked inside a rote civic exercise is not a prayer. Mr. Newdow's daughter is not required to say either the words ''under God'' or even the pledge itself, as the Supreme Court made clear in a 1943 case involving Jehovah's Witnesses. In the pantheon of real First Amendment concerns, this one is off the radar screen.

The practical impact of the ruling is inviting a political backlash for a matter that does not rise to a constitutional violation. We wish the words had not been added back in 1954. But just the way removing a well-lodged foreign body from an organism may sometimes be more damaging than letting it stay put, removing those words would cause more harm than leaving them in. By late afternoon yesterday, virtually every politician in Washington was rallying loudly behind the pledge in its current form.