Russia, US and China Playing with Ukraine, Syria, Iraq, Yemen and Iran Cards

[W]hat is to stop Iran from actually embarking on a nuclear weapons program, since it is already being subjected to these sanctions?

The central objective of increasing the security and military costs imposed on Iran is not necessarily to launch an all-out war, but rather to compel the Iranian leadership to accept a new deal.

Unless Trump is persuaded to return to the negotiating table, this cycle of violence is bound to persist.

While one can go to war alone, returning in the same manner is impossible unless a knockout blow is achieved.