However, separation is not extended to bar religious conduct in public places or by public servants. Public servants, up to and including the President of the United States, often make proclamations of religious faith. Sessions of both houses of the United States Congress and most state legislatures typically open with a prayer by a minister of some faith or other, and many if not most politicians and senior public servants in Washington, DC attend the annual Roman Catholic Red Mass at the Cathedral of St. Matthew the Apostle regardless of their personal religious convictions. In contrast to France, the wearing of religious insignia in public schools is largely noncontroversial as a matter of law and culture in the U.S.; the main cases where there have been controversies are when the practice in question is potentially dangerous (for instance, the wearing of the Sikh "kirpan" knife in public places), and even then the issue is usually settled in favor of allowing the practice. In addition, the U.S. government regards religious institutions as tax-exempt non-profits, subject to limitations on their political involvement. Moreover, the military includes government-paid religious chaplains to provide for the spiritual needs of soldiers. In contrast to Europe, however, the government cannot display religious symbols (such as the cross) in public schools, courts, and other government offices, although some exceptions are made (e.g. recognition of a cultural group's religious holiday). In addition, the United States Supreme Court has banned any activity in public schools and other government-run areas that can be viewed as a government endorsement of religion.