Hell, his tactical advantage in the shutdown hasn't been anything having to do with a deliberate negotiating position as much as it probably is that he just doesn't give a fuck about it as much as everyone else. One reason the White House seemingly had no position until they threw together that package and he was like alright, whatever.
Once you're President, the only real validation that exists is your re-election. Look at how two-termers are treated generally, even if their second term sucks, even if they're Nixon, compared to any single termer. Even Truman and LBJ often don't totally escape the fact that they were only elected once. (And both benefit quite a bit from the way they were elected, a surprise and a landslide.)