1. Iran had an election shortly after JCPOA. If that election would have led to a change in government, and under the new president, Iran had decided to abrogate from the agreement, would the argument then be "hey, fair enough, it was not a a treaty"?
2. The senate passing it makes no difference. The Republicans, controlling the House and the Senate, may well have been successfully in passing legislation withdrawing from the treaty. Except - that isn't even necessary. Trump can withdraw from any treaty he likes whenever it pleases him: https://www.washingtonpost.com/news/monkey-cage/wp/2018/05/0...
All of these are simply internal American processes, and it is up to the Americans to consider wether they want their politicians to run a foreign policy that projects stability, where the decisions of previous presidents are maintained because, being legitimately elected it was their decision to make, and American's word should stand for something - or whether they want their country to be perceived as erratic - which is in fact the case now, whether or not it causes allies such as the EU to ultimately make real changes in the relationship.
Strong political polarization in the US guarantees that going forward there won’t be continuity between presidents because there’s likely to be rapid shifts back and forth across the political spectrum
2. The senate passing it makes no difference. The Republicans, controlling the House and the Senate, may well have been successfully in passing legislation withdrawing from the treaty. Except - that isn't even necessary. Trump can withdraw from any treaty he likes whenever it pleases him: https://www.washingtonpost.com/news/monkey-cage/wp/2018/05/0...
All of these are simply internal American processes, and it is up to the Americans to consider wether they want their politicians to run a foreign policy that projects stability, where the decisions of previous presidents are maintained because, being legitimately elected it was their decision to make, and American's word should stand for something - or whether they want their country to be perceived as erratic - which is in fact the case now, whether or not it causes allies such as the EU to ultimately make real changes in the relationship.