Gee, a lot of people don't understand the difference between teaching ABOUT religion and PROSELYTIZING. And a lot of people are evidently misinformed on what the Founders intended in the first amendment.
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
A clear reading of the words compels the government to ensure that there is no prohibition on the free exercise of religion. Congress shall make no law respecting the establishment of a religion. C'mon, my third grader can understand "Congress shall make no law," and the difference between that and "The cheerleaders at MLK High School want to pray before a football game. In fact, Congress MUST ensure there is no prohibition on free exercise of religion.
So hello all you smart folks: can Congress make a law saying schools may not teach religion? Again, anyone with a lick of common sense could see that that is prohibited by the second clause - it is a prohibition on free exercise.
But that's not my point. Religion is a huge part of the vast majority of lives around the globe. From a practical sense, prohibiting schools from teaching what that's all about cuts a vast cultural swath in the eduction of our children. Schools that don't teach ABOUT religion (because of misinformed interpretation by anti-religion zealots) are handicapping their students.