"Article VI, paragraph 3 of the U.S. Constitution declares, that 'no religious test shall ever be required as a qualification to any office or public trust under the United States.' This clause is not introduced merely for the purpose of satisfying the scruples of many persons, who feel an invincible repugnance to any religious test, or affirmation. It had a higher objective: to cut off for ever every pretence of any alliance between church and state in the national government."