Constitution does NOT require "Separation of Church and State"

First Amendment reads "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof;"  That is the first sentence of the first amendment, so we can believe that the issue was important to the founders.
   In the eighteenth century, when the Constitution was created, establishment of religions was a fairly common practice in the world.  In England the Church of England was established.  You had to be a member of the Church of England to receive important government jobs like judgeships, commissions in the army or navy.  The royal family was required to be Church of England members. In France you had to be catholic to hold just about any job, public or private.   In short the established church received benefits at law and favored treatment. 
   America had a lot of different churches in the eighteenth century, Congregational, Quaker, Episcopal, Catholic, and others that I don't remember.  All of which would have been proud to become established. 
   First amendment says that no church gets the bennies of establishment, all churches get treated the same in the eyes of the law.  Which surely ended a lot of jockeying for position and fear that some other church would gain the bennies of establishment.  In short it was a good political compromise.  Second clause about the free exercise thereof means that churches are free to put up church buildings, conduct services, pass a collection plate, marry people, operate schools, send out missionaries, bury parishioners in the church yard, and do all the other churchly things.  Including putting up a cross as a memorial to WWI dead.
   The Supremes just ruled that cross legitimate.  They mentioned a number of good reasons, such as it had stood for close to a century, but they did not come right out and say that putting up a cross is free exercise of religion, which they should have done. 
    The phrase "separation of church and state" I believe comes from Thomas Jefferson, not the Constitution.  Granted, Jefferson was a heavy duty founder, for whom we have a lot of respect, but he didn't get separation of church and state into the Constitution.