TEHRAN, Iran — The diplomacy of smiles between the United States and Iran has come to an end. Not even regular old diplomacy seems to be an option anymore, with US President Donald Trump clearly stressing the importance of countering what he calls the Iranian regime's "destabilizing activity and support for terrorist proxies in the region.”

Trump took things back to square one, undoing the path that was paved during two years of marathon negotiations between diplomats and experts from Iran, the United States and the other world powers that negotiated the Joint Comprehensive Plan of Action in different venues around the world. The nuclear deal, struck in July 2015, was seen as a required step before there could be any cooperation between Tehran and Washington on regional crises, mainly Syria and Iraq.

The possible collapse of the deal and the new US strategy on Iran is expected to raise the level of regional tensions, given the blatant hostility between Iran on one side, and the United States and its main regional partners on the other. This alone should elicit concern over precarious possibilities on several fronts, mainly in Iraq, Yemen, Syria and Lebanon — countries of continuous political and military tensions. To Iran, it’s clear Trump is mainly cooperating with Saudi Arabia and Israel in efforts to stop the Islamic Republic of Iran from making gains in the Middle East.

The United States and its partners "are straining to find a way out of their failures,” a source within the Islamic Revolutionary Guard Corps (IRGC) told Al-Monitor on condition of anonymity. “In Syria and Iraq, it’s Iran with the upper hand, despite what they try to say and portray.”