During the 2017 presidential campaign, then-candidate Donald Trump was open about his hostility toward Iran and his disdain for the Obama administration’s diplomacy with that country.

Since January, the Trump administration has been engaged in an Iran policy review. News reports and leaks suggest the review is highly likely to recommend a more confrontational approach to Iran, whether within the framework of the Iranian nuclear deal or by withdrawing from it.

This paper examines the costs of four confrontational policy approaches to Iran: sanctions, regional hostilities, “regime change from within,” and direct military action.

Increased economic sanctions are unlikely to succeed in producing policy change in the absence of a clear goal or multinational support. Indeed, sanctions on Iran are likely to meet with strong opposition from U.S. allies in Europe and Asia, who continue to support the nuclear deal.

The second policy we examine — challenging Iranian proxies and influence throughout the Middle East — is likewise problematic.

There is little coherent, effective opposition to Iran in the region, and this approach increases the risks of blowback to U.S. forces in the region, pulling the United States deeper into regional conflicts.

The third option, so-called regime change from within, is a strategy that relies on sanctions and on backing for internal Iranian opposition movements to push for the overthrow of the regime in Tehran.

This approach is not feasible: regime change — whether covert or overt — rarely succeeds in producing a stable, friendly, democratic regime. The lack of any good candidates for U.S. support inside Iran compounds this problem.

The final policy alternative we explore is direct military action against Iranian nuclear or military facilities. Such attacks are unlikely to produce positive outcomes, while creating the risk of substantial escalation.

Worse, attacking Iran after the successful signing of the nuclear deal will only add to global suspicions that the United States engages in regime change without provocation and that it cannot be trusted to uphold its commitments.

We suggest an alternative strategy for the Trump administration: engagement. This approach would see America continue to uphold the nuclear deal and seek continued engagement with Iran on issues of mutual interest.

Engagement offers a far better chance than confrontation and isolation to improve Iran’s foreign policy behavior and empower moderate groups inside Iran in the long term.

Read the rest of the paper at CATO Institute.