You misread what I typed. The other parties to the agreement will not be interested in reimposing sanctions IF the United States bails on the agreement. The agreement is structured so that sanctions snap back automatically absent a certification that Iran is in compliance, and Russia and China cannot veto or block.
The simple fact of the matter is that we are where we are right now, whether you agree that Obama should have brought us here or not. There is no going back to the way things were before, so the question is, WHAT do you hope to accomplish by having the US unilaterally reject this agreement?
What they hope to accomplish is complex.
First off, they have a compulsive need to beat Obama, at everything, and will create adversarial positions for that purpose alone.
Next, they want to maintain an irrational electorate, one distracted by their bullshit. It's like Mussolini puffing out his chest. In that, they want to retain the possibility of aggression on our part by maintaining a high tension level.
They also want to maintain favor with the Israel lobby and to advance the goals of the State of Israel. The Neocons are thick as thieves with Bibi's crew.
Few people in this country understand that the current situation in Iraq & Syria was the desired result all along. Fractured & fighting amongst themselves, they won't be a realistic threat to Israel for at least a generation.
The same minds that engineered that feat would very much like to do the same thing with Iran.