Fold. The opener, although he probably doesn't correctly understand, doesn't have enough chips to raise/fold and your hand isn't strong enough to face an all-in situation by him.

Also, he's playing almost 40% of hands but hardly raising so the fact he 3X's here means you need to asisign him the stronger end of his playing range which makes this even more of a fold spot.

You flop awful against hands which call you – better Ace hands, pocket pairs, KQ … when you re-steal you don't obviously need the best hand but you want one which can outflop the hands that call you.

I'd rather re-steal with JT suited than A3 offsuit any day.