With Trump so despised and isolated with the Europeans, China, Japan and S. Korea, the IR Regime is seeing an opening to demand more from the aforementioned countries to stay in the Nuclear Deal. There’s zero chance that anyone will go along with Trump to re-instate the oil and banking sanctions that brought the Regime to the table in the first place, and zero chance of renegotiating the Deal with Trump.

So, the Europeans will just throw more concessions and investments at the Regime to keep them in the Nuclear Deal.

The problem for the IR is though that even if these countries don't go along with sanctions, the U.S. imposing its unilateral sanctions will have --for the most parts--the same conseqeunce. Most of the European, Japanese, and even the Chinese companies that are interested in doing business in Iran also have business interests in the U.S. And if the U.S. imposes sanctions on Iran, those companies will not be able to do business in Iran because they'll be in violation of U.S. laws while they do business in the U.S. And the U.S. is a much bigger business partner for companies around the world than Iran. So, most will abandon their business interests in Iran. The IR knows this very well. That's why they're getting nervous.  

What you described is called the Secondary Sanctions. The Europeans and the Asians went along with the US threat because Obama had a "carrot and stick" strategy and wanted to resolve the nuclear issue peacefully.

But when Trump brought up the issue of the secondary Sanctions, China and others said that it will result in a trade war with the US, and it was unfair.

As long as the Regime keeps its nose clean regarding the nuclear enrichment, it will have the edge over the US. See, Total, VW, Renault, Peugeot and others are already there with investments with no fear of a backlash in the US.

Trump could've stopped the sale of Boeing and Airbus to Iran but he chose not to do it.

There is a huge amount of Bluffing going on here. The IRI and its paid spies here and there know damn well that the regime's officials and decision-makers do not have the intestinal fortitude to make even one wrong move.

IRanians have so far had millions of chances to actually go back and re-start the whole project but they DID NOT and that says a lot about their actual and practical capabilities to put anything of substance out there.

This is a typical case of Iranian style of boasting about the power that does not exist. U.S. and the rest of the singnatories to the nuclear deal are best to ignore all this huffing and puffing.