Ehud Barak, Israel’s Prime Minister from 1999 to 2001, believed his country’s Arab adversaries would be more afraid if Tel Aviv behaved in an unpredictable way. As long as Israel was predictable, Barak’s thinking went, outrageous acts of terrorism would continue to be inevitable. Known as “the landlord went crazy,” the strategy was employed by Dan Halutz, the then Israel Defense Force chief of staff, in the Second Lebanon War in 2006 and the Gaza operation in 2008.

The confession of Hezbollah secretary general Hassan Nasrallah, after the Second Lebanon War, that if had he known Israel would “go crazy” in response to the ambush and abduction of its soliders, he would not have made such a mistake, reveals the effectiveness of the crazy-landlord strategy, and indeed Israel’s failure to convey that message to the terror group at the time.

Similarly, the United States has failed to convey an adequate message of deterrence to the Iranian regime during the past 37 years. Since 1979, Iran has adopted a unique posture involving the export of its own particular brand of Islamism; defiance of international norms; a pursuit of hegemony over the Middle East; a quest for nuclear weapons; and, most consequentially of all, declaring jihad against the United States.

On November 4, 1979, Khomeinists stormed the American embassy in Iran’s capital, Tehran, taking more than 60 diplomats captive for 444 days. The episode was followed by the kidnapping of US citizens in the region – between 1982 and 1992, 30 US citizens, among them CIA station chief William Buckley, were taken hostage. Then and now, the Iranian regime has funded – and provided equipment, weapons and training to – terror groups aligned against US interests. To be more accurate, terrorism has served as a weapon in the regime’s struggle against the US presence in the Middle East.

The Revolutionary Guards and the Quds Force — the Guards’ foreign operations unit — have orchestrated a reign of terror to destabilize both neighboring countries and territories further afield. The regime is said to be responsible for many terror plots, either through the Quds Force or its proxies, Hezbollah and Hamas. As a Marine, Donald Trump’s new Secretary of Defense, General James Mattis, is well aware that the Iranians sponsored the infamous 1983 attacks on the Marine Barracks in Beirut which killed 241 American soldiers.

The US intelligence community believes that the Iranian regime, with the support of Hezbollah, carried out the Khobar Towers attack in Saudi Arabia in 1996 that killed a large number of American citizens. Additionally, classified documents released by WikiLeaks in July 2010 indicated that the Revolutionary Guards had been collaborating extensively with al-Qaeda and the Taliban since 2001, and carried out numerous attacks on coalition forces in Iraq and US troops in Afghanistan.

More recently, the Revolutionary Guards has steadily expanded its missile arsenal and increased its efforts to develop intercontinental ballistic missiles (ICBMs) capable of carrying nuclear payloads and striking targets in the United States. Iran has, in fact, test-fired missiles marked “Israel must be wiped out.”

Moreover, Iran’s Sepah Navy Special Force has been involved in eight confrontations with American vessels patrolling the waters of the Gulf since July 2015. Defense Minister Hossein Dehghan has said his warships will continue to confront any US Navy ship in the sea.

In January 2016, the unit seized two American riverine boats with 10 personnel aboard who were held overnight. Propaganda videos released by Iranian TV showed Americans soldiers blindfolded and kneeling. The message was clear: Iran believes it can continue its aggressive behavior with no response from the world’s superpower. Iranian Navy speed boats have also engaged in aggressive maneuvering against American vessels in the Strait of Hormuz.

In a more ominous turn, an increasing number of American citizens – many of whom stand accused of spying or attempting to undermine the Iranian system – have been arrested since October 2015.

These cases demonstrate Washington’s failure to convey to the regime in a timely manner its seriousness about “going crazy.” Even President Trump’s threat to “apply the toughest sanctions” to Iran will do little to convince the Revolutionary Guards of his seriousness. It is important to note that while Iran was under the toughest sanctions regime in history, the Revolutionary Guards stepped up its destructive behavior.

President Trump must abandon the notion to which the Obama administration has clung: that Iran might become a normal state in the global community. The minute a lack of American determination is detected, the Revolutionary Guards will continue their evil ways. The regime must be convinced that Washington will “go crazy” and strongly retaliate in the event of the Guards or Quds force taking any missteps —as it did, for instance, in Operation Praying Mantis, in the last year of the Iran-Iraq war.

To recall, on April 14, 1988, in what was the largest naval engagement since World War II, US forces sank two Iranian warships and three armed speedboats and attacked offshore rigs, in retaliation against Iran’s mining of the Persian Gulf and subsequent damage to an American warship.

The behavior of the Iranian regime in general and the Guards in particular follows a special pattern. Goodwill gestures from Washington achieve nothing – they only embolden the Revolutionary Guards. As a high-ranking member of the Guards, speaking to me recently on condition of anonymity, put it: “Washington’s appeasement will only provide the regime with more room to maneuver.”

What Trump needs is a comprehensive policy to contain Iran. Engaging Iran by punishing it for its ballistic missile program would be a good place to start. There are certainly serious concerns about Iran’s long range missiles since the cost-benefit analysis does not justify mounting conventional payloads. Trump should also put a policy together to punish the regime for its sponsorship of terrorism, reverse Iran’s external advances and counter its military intervention in the region –including in Iraq, Syria and Yemen.

Fortunately for Trump, both Gen. James Mattis and Gen. Michael Flynn have strong opinions on Iran and will hope to punish Iran for its involvement in terrorism. Both view Iran as a leading sponsor of Islamist terrorism, either through the Quds Force or its numerous proxies all over the Middle East. The United States has an arsenal of tools, including covert operations and sophisticated cyberwar tools which can be used against the Iranian regime.

Disclaimer: The viewpoints expressed by the authors do not necessarily reflect the opinions, viewpoints and editorial policies of IRAM.