We learned from Vietnam that wars of attrition are for fools. The corollary is that nation building is for fools. (It makes me wonder why General Colin Powell supports Obama).
George W. Bush knew this and said he would not do nation building. But the Democrats shamed him into it after Bush dethroned Saddam Hussein and it was discovered that there was no end game.
Clinton and Obama sure didn't do any nation building after they destroyed Lybia. Fully destroyed Lybia. One liberal I knew resolved the cognitive dissonance of Bush being a war criminal and Clinton/Obama not being a war criminal even though Bush was more humane with his nation building attempt, by declaring the Lybia was too small so it didn't matter. Liberals always resolve cognitive dissonance by believing the untrue.
Syria is a proxy war and proxy wars are wars of attrition.
I don't do proxy wars and I don't do wars of attrition. You don't want me as president.