The problem with that is Pakistan harbors around 100000 terrorists of every Muslim terrorist group you could imagine (Al Qaeda, Taliban, etc) that are certainly "pro" death to america, if alive this is almost certainly where Bin Laden is hiding, one might infer that their protection of these groups and allowing them a place to reconstitute their forces, while simultaneously the US invades Iraq and Afghanistan looking for these same groups but somehow unable to find them, might constitute being a terrorist state.
Also given the massive # of terrorists in Pakistan already compared to relatively weak national security there even if Pakistan is just complacent and doing nothing (laziness perhaps? ) to eliminate them rather than actually support them as the terrorist #s grow they could simply takeover the Islamic country's government in a coup thus instantly becoming a 100 nuke armed terrorist run state.
One really has to wonder why a country would harbor terrorist groups in the first place? They're an incredible national security threat (Pakistan has constant terrorist attacks) as well as of course international threat, but this is what Pakistan chooses to do for some unknown reason