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.
-The First Amendment, United States Constitution
By forcing companies to provide the morning after pills, they are "prohibiting the free exercise" of said companies religious beliefs. According to a recent ruling by the supreme court, private enterprises are considered individuals, and the rights listed in the Constitution apply to private employers.