Tehran's conventional deterrence appears no less threatening to the region. Its centerpiece is a ballistic missile program - a legacy of having been a victim of these during the Iran-Iraq War. As the only Iranian weapon that could reach its adversaries on their soil, the missiles are deemed an existential asset by Tehran, which will pursue their development regardless of whatever sanctions are imposed. The Iranians refused to put their missiles on the bargaining table during the nuclear negotiations and are unlikely to compromise on them, absent fundamental changes to the region's security structure of which Iran would be an integral part.

It's hardly surprising that what looks defensive from Tehran would be perceived elsewhere as aggressive. But what makes Iran's regional policy seem especially menacing is the second impetus behind it - its desire for regional power status, which to neighboring capitals looks like a bid for hegemony. To them, that scenario is as unbearable as Iran's isolation from the region is unacceptable to Tehran.

Any U.S. policy toward Iran's regional ambitions must take these dynamics into account. This will allow Washington to develop a realistic assessment of Tehran's likely reactions, of which the following are the most obvious: