There is a thing about studying history that makes the Enlightenment Philosophers basically the Church Fathers of Modernism. They're always quoted and hailed as geniuses, etc. I used to really like them, but the more I read of them, and the more I read of Aquinas, the more and more I hate them, the more and more I like St. Thomas.
"If the triangles made a god, they would give him three sides." - Montesquieu
"No kingdom has shed more blood than the kingdom of Christ." - Montesquieu
On the Contrary, Aquinas states that God's essence is an unknowable mystery, and that we can only really speak of him in Analogies because he is so infinite and mysterious.
In response to the second question I'd say that it really depends on your definition of "kingdom of Christ", if he means "the Church"/Catholic Church, he's wrong, as technically the Church has never executed a single person, STATE GOVERNMENTS did. Throughout all the Middle Ages and even to the early modern period, the State had heresy laws and the Church was usually hired as the 'advisor' to whom might be the heretic, or rule breaking person in question.
And if we extend his statement to modern times, Mao killed more than every church did combined.
So there, Montesquieu, go inspire Americans to rebel against England based on faulty Natural law theory and then die after having your books banned.. oh wait, you already did that. ...Score one for Aquinas.
Taunting the dead is a favourite passtime of the history student.