Ariane Tabatabai reviews  Iran’s foreign policy ahead of the 40th anniversary of the revolution, and explains that Tehran’s foreign policy isn’t as ideologically-driven as the administration thinks:
This is because, contrary to what many believe, Iran’s foreign policy today is largely shaped by its threat perceptions and interests—not ideology.
Because the contours of Iran’s foreign policy appear to be drawn primarily by security considerations, including deterrence and power projection, the United States isn’t likely to fundamentally change the country’s behavior.
American policymakers have several blind spots when it comes to understanding the behavior of other governments, especially when they consider them to be adversaries. The worst of these is the tendency to ascribe profound ideological motives to a regime’s leadership when they are usually concerned much more with self-preservation and protecting their national interests as they understand them. During the Cold War, many anticommunists imagined that the Soviets were much more bent on pursuing a revolutionary foreign policy than they actually were. Those who understood that Soviet foreign policy had a great deal of continuity with the policy of pre-revolutionary Russia were more likely to make sense of what the Soviets were likely to do and why they were doing it. Interpretations of other states’ behavior that reduce everything to the official ideology of that state are always going to miss the mark because the real reasons for their conduct are to be found elsewhere.
Prior to the negotiation of the nuclear deal, Americans were regularly treated to nonsensical “analysis” that portrayed Iran as a fanatical government prepared to commit national suicide in pursuit of its goals abroad. This  “martyr-state”  myth  has thankfully been thoroughly  debunked  and discredited by events, but the fact that it flourished  at all  shows how determined many American policymakers and pundits are to perceive their adversaries as irrational, inflexible maniacs that cannot be deterred or reasoned with.
Iran hawks in the Trump administration still insist on describing Iran’s policies in terms of exporting revolution. Pompeo said  as much in his widely-panned article for Foreign Affairs from last year:
The regime’s revolutionary mindset has motivated its actions ever since—in fact, soon after its founding, the IRGC created the Quds Force, its elite special forces unit, and tasked it with exporting the revolution abroad. Ever since, regime officials have subordinated all other domestic and international responsibilities, including their obligations to the Iranian people, to fulfilling the revolution.
As Tabatabai explains, this is a dated interpretation that ignores the changes in Iran and its government over the last four decades:
But a closer assessment of the regime’s foreign policy unveils a much more pragmatic Iran, one whose policies are nonetheless shaped by its historical experiences and culture.
The Trump administration can’t or won’t acknowledge the existence of this “much more pragmatic Iran,” because that would be an admission that their own uncompromising hard-line approach is unnecessary and harmful. They need to portray Iran as a destabilizing revolutionary state to make their obsessive hostility to Iran seem more defensible, but it is all based on a faulty understanding of the country and its government. That in turn has led to the administration’s preposterous demands that Iran radically alter its foreign policy, but that won’t ever happen because Iran considers its current policies to be important for their national security and for the survival of the regime. Far from being the self-destructive revolutionaries that Iran hawks want them to be, Iran’s leaders are interested in self-preservation above all else. The U.S. needs to have an Iran policy that takes that into account, or else we will continue to have a failing and bankrupt Iran policy that achieves nothing besides deepening the enmity between our governments.