The First Amendment is a muscle that must be used, or it will become flabby. A survey of high school students by the John S. and James L. Knight Foundation reveals a frail Constitution: Kids are weak in knowledge of their rights.

* 73 percent said they didn’t know how they felt about the First Amendment or took freedom of speech and the press for granted.

* More than a third (35 percent) thought that the First Amendment goes too far in protecting rights.

* One in six students indicated that people shouldn’t be allowed to express unpopular opinions.

* Only half said newspapers should be allowed to publish freely without government approval of stories.

The apathy is alarming. Those who don’t understand the First Amendment are certainly less inclined to exercise it, and they’ll be less skeptical and more easily conned by government officials who want to twist and limit it.

Ignorance is not kids’ fault. Unawareness starts at home. Parents’ understanding of the First Amendment isn’t much better. Even in the best of times, three out of 10 adults believe that the First Amendment goes too far. That belief jumped to half in the months after Sept. 11. Talk-show hosts like Rush Limbaugh make good money assailing the credibility of mainstream journalists and of anybody who disagrees with him.

In school, First Amendment-rich electives are getting left behind in the race to raise test scores in math and English. California requires three courses in social studies, including a semester course in American government and civics. But often, the focus is on specific information found on state history and social studies tests, not on broad concepts.

Schools need to convene more discussions of controversial issues and to promote civic involvement outside of class.

The Knight survey of 100,000 students in 544 high schools found a clear correlation between knowledge of the First Amendment and participation in a school radio station or newspaper. One-quarter of schools no longer publish papers, and many of those that have dropped them are in poor communities.

The exhilaration that Iraqis felt in voting for the first time should remind Americans of rights they often don’t appreciate. An atrophying First Amendment is harmful to the nation’s civic health.