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I'd be tempted to call. Do I understand correctly - if you go all in, he's got another 1400 to call if you go all in? In which case, he's calling, no? In this case, there is no benefit to pushing all your chips in - I would wait for the flop and see what he does and he will act first.

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Because he is first to act, if any overcard hits you'll be put in a tough spot. would you call his all-in? What if he has AQ and the king hits. He could bluff you off it here with a stop-and-go all in.

The point of the All-in preflop is that only AA KK QQ have you hurting, and the range of hands you put him on after his raise is much much broader than that. Something like [AJ and up, PPairs 88 and up, and KQs] is plausible.

There's always the chance that he has the bigger pair, but second guessing pairs with natural strength like Jacks in limited-info situations like this is -EV... it leads to less wins because you are afraid of being maximally agressive. The risk of KK vs JJ is just the risk you take playing poker. If he has you beat, make him prove it, and take your 20% chance of trips as a little consolation prize.

As an aside, Phil Gordon mentions in his Little Green Book that "The Fourth Raise is Ususally Aces."

So if you did re-raise him with your jacks in a deeper-stack situation, and he came back at you all-in, you would have a bit more information and would be able to make a laydown.

The size of the stacks relative to the chips in play (READ: POT ODDS) is the important factor in the decision to push here (other than the strength of the pair of course)

Cheers.