It’s Tehran’s turn for the “fire and fury” treatment.

In response to Iranian President Hasan Rouhani telling Donald Trump not to “play with the lion’s tail” because “war with Iran is the mother of all wars,” the president fired back in an emphatically all-caps tweet warning of “CONSEQUENCES THE LIKES OF WHICH FEW THROUGHOUT HISTORY HAVE EVER SUFFERED BEFORE.”

Since the last time Trump theatrically threatened a regime with destruction he quickly turned around and had warm talks with Kim Jong Un in Singapore, his Twitter account has lost some of its deterrent force.

But the exchange of words has focused attention on a growing confrontation with Iran, in which the United States has the upper hand. When Trump pulled out of the Iran deal earlier this year, there were warnings that it would split the Western alliance, prompt an Iranian nuclear breakout or leave the U.S. isolated and unable to effectively sanction Iran on its own.

Instead, Iran is in the midst of an economic crisis before the U.S. has truly ratcheted up the pressure. In less than a year, the Iranian currency, the rial, has lost half its value. There have been broad-based demonstrations around the country. Major multinational companies are pulling back from doing business in Iran, including General Electric, Siemens and A.P. Moller-Maersk.

Iran wasn’t in position to take economic advantage of the windfall of the nuclear deal. It was most interested in funding its terrorism and foreign adventurism, and even if it weren’t, its economy is hopelessly corrupt. Despite then-Secretary of State John Kerry urging Europeans to do business in Iran, the terror state obviously doesn’t present a stable business climate. (The governor of the Central Bank of Iran has been sanctioned by the U.S. Treasury for helping the Revolutionary Guards funnel funds to Hezbollah.)

U.S. sanctions that were lifted as part of the Iran deal begin to snap back on Aug. 6, and the administration has a goal of getting Iranian oil exports to zero by November. Although this isn’t realistic, and the administration will grant exceptions to some allies, Iran could lose 1 million barrels a day in exports (in May, its exports had hit a new record at 2.7 million barrels a day).

This is nothing less than financial warfare against the regime, aimed at denying it hard currency to fund its foreign operations and ultimately at destabilizing it. The administration denies that it has a policy of regime change, but Secretary of State Mike Pompeo’s demands for a new deal are so sweeping and fundamental that Tehran couldn’t comply short of a radical reorientation toward becoming a normal state.

The economic campaign is coupled with a strategy of backing our allies — Israel, Saudi Arabia and the United Arab Emirates — to the hilt in resisting Iranian aggression in Syria and Yemen.

This is all to the good. The problem is that Trump’s desire to get out of Syria entirely is at cross-purposes with pressuring Iran on all fronts, and the hope that a cynical and self-interested Russia will significantly aid us vis-a-vis Iran is surely misbegotten.

With proxy forces across the region, Iran has cards to play, and the regime is inherently dangerous. At a time when it should be doing everything to curry favor with the Europeans, one of its diplomats was arrested a few weeks ago in Germany for plotting a terror attack on an Iranian opposition group in France.

But Iran lacks several advantages enjoyed by North Korea. It doesn’t have an overwhelming, powerful patron like China. It unites Israel and the Arab states, and none of our regional allies are pressuring us to negotiate with Tehran the way South Korea pushed us to talk with Pyongyang. Finally, Iran doesn’t yet have nuclear weapons.

This gives the administration leverage. The mullahs shouldn’t fear presidential tweets as much as the economic clampdown to come.

Rich Lowry is a syndicated colulmnist. He can be reached via e-mail at: comments.lowry@nationalreview.com.

Rich Lowry