The United States and Iran will have their highest-level interaction of Donald Trump's presidency on Wednesday, a day after the American leader delivered a blistering attack on the Islamic Republic and the landmark 2015 nuclear deal that he appears poised to walk away from.

A year ago, such a get-together would have been considered routine as nations strove to implement an agreement that curtailed Iran's nuclear activity in exchange for ending various oil, trade and financial restrictions on the country. In the current environment, however, the meeting is anything but ordinary.