[jgorham]

Easy 3bet. If villain has 2pair or a set here, it is impossible for him to have a spade, which makes your three look especially nice. But besides all that, LAG's will make this play with AXs fairly often. Or even AK or AJ.

Edit: Thinking makes this 3bet even easier - you would have been 3bet preflop by AA, QQ or AQ. Perhaps even A2 depending on the lag. So he could have 22 or 33 here, but there are a lot of other hands he probably has which you are ahead of. Plus you will outdraw 22 and 33 fairly often.