Basically, asking someone their evaluation of the war in Afghanistan is tantamount to asking them their party identification. If you're of the same party as the president, you're okay with it. If not, you're not. Of course, it isn't a perfect mirror -- Republican support for the war under Bush was more than ten points higher than it is among Democrats under Obama. This, however, is surely reflective of the substantial chunk of the Democratic electorate that is fundamentally anti-war no matter who the president is, and not an evaluation of the president's actual prosecution of the war.