TEHRAN - John Limbert, the former U.S. deputy assistant secretary of state for Iran, says muuch of Trump's position about Iran is “posturing  for his base of Obama-haters.   Iran is simply a tool to feed that base.”

Limbert, also tells the Tehran Times that “The anti-Iranian language in the statement carries the fingerprints of those far-right groups both in the U.S. and elsewhere who oppose ANY engagement with the Islamic Republic.”  
Following is the text of the interview:

Q: U.S. President Donald Trump approved the Iran nuclear deal only one more time before abandoning it if it is not changed. What are the changes that Trump emphasize on them? 

A:  If you read Trump's January 12 statement it's clear that he does not care about Iran and the JCPOA.   His actual target is Obama, whom he criticizes twice in the statement.   The only other people he mentions are "the leader" (once) and Bashar Asad (once).   If he could sanction Obama, he would. 

To put it mildly, Trump is obsessed with Obama.   He is upset that Obama's approval rating (50-60%) was much higher than his (about 35%).   Notice his fixation on "crowd size" at his inauguration.   Furthermore, Trump always presents himself as a master negotiator and he cannot admit that someone else would make an agreement that is good for the U.S.   His whole being depends on denigrating others' achievements. 

The anti-Iranian language in the statement carries the fingerprints of those far-right groups both in the U.S. and elsewhere who oppose ANY engagement with the Islamic Republic.  Their goal seems to be returning to the older pattern of non-relations and exchanges of threats, insults and accusations.   They opposed the JCPOA not because of its contents but because it represented a different way of dealing with Iran.   They opposed the whole idea of diplomacy. 

Q: Mr Trump also wants Iran's ballistic missile programme to be addressed. Iran frequently has emphasized that ballistic missile is not related to JCPOA and will not negotiated about it. According to this, do you think that this condition meaning the end for JCPOA?
A: Much of Trump's position is posturing for his base of Obama-haters.   Iran is simply a tool to feed that base.

He has given other members of the P5+1 and ultimatum: you renegotiate the agreement with Iran.   They will not do it and the Iranians will not agree. 

I suspect there are some expatriate Iranian hands involved in the statement.   Some of them still blame Obama for the failure of the Green movement in 2009.   Their extreme dislike of Obama corresponds with Trump's dislike.   A poisonous mixture, in my opinion.
Remember that Trump's dislike of the JCPOA has nothing to do with its contents.