When Lee chose to fight against the Union he did it with great deliberation and much angst.  In the end Virginia was what was important.  Allegiances were greater toward home (states) than to the Union.  It was a tipping point for many.  He didn't make the decision to go to war, that was Lincoln and Davis, and mostly Lincoln pushing it rightly or wrongly.  Lee made the decision on what side to fight for and he chose home.  That is why brother fought against brother more than any other reason.  Lee is an American Hero.  This from a yankee.