[dsaxton]

I would raise here. The pot is becoming large, and there is some chance that your aces are actually ahead, in which case not raising is a big mistake. If he happens to have two pair, then raising and betting 6th at worst only costs you a small amount of expectation, since you get the pot heads-up and have plenty of outs to improve to a winning hand anyways. The value of isolation might even make it a winning play, but I'm not sure.