Philander refers to Philander C. Knox, U.S. Attorney General under Teddy Roosevelt, Secretary of State under Taft, and then a Senator who sponsored the bill ending World War I. You may have heard one of his quotes, said to Teddy Roosevelt concerning the legality of America's involvement in the construction of the Panama Canal: Mister President, do not let so great an achievement suffer from any taint of legality.
That got appropriated in the screen play for The Wind And The Lion (at around 2:15):
Philanderer, of course, refers to the 42nd President of the United States. He didn't let his actions suffer from the taint of illegality either, but other than that, it's quite a difference that a syllable makes.