Iranian Supreme Leader Ayatollah Ali Khamenei speaks during a meeting with students in Tehran, Iran on Oct. 18, 2017. Iranian Leader's Press Office - Handout | Anadolu Agency | Getty Images

Surprising new signs are emerging that President Donald Trump's controversial "maximum pressure' campaign on Iran could set the table for new negotiations toward a better agreement. To get there, however, Trump will have to navigate the greatest perils in U.S.-Iranian relations in recent memory – something he has done so far with a military restraint that has confounded his critics and gained him praise for "prudence" even from Iran's foreign minister. Since late April, when the Trump administration ended waivers on eight countries that allowed them to continue to buy Iranian oil, Tehran's exports have nosedived to some 300,000 barrels a day from more than a million previously. Its economy has shrunk by 6%, and its currency has lost 60% of its value over the past year. The immediate impact of that escalated U.S. economic pressure has been the most dangerous ratcheting up of Iran's threatening activities in memory, which one senior U.S. official explains as Tehran "punching its way toward new talks." Iran has begun to breach the nuclear deal's enrichment restrictions, it shot down an American drone, and it now has seized a British tanker. This week, Tehran announced plans to execute a ring of alleged CIA spies. Beyond that, Iranian-backed Houthis in Yemen have been using drones and missiles provided them by Tehran to strike Saudi targets such as airfields, pipelines and pumping stations. Iranian trained and financed Shia militias are firing rockets at U.S. bases, and Israeli security officials have told former U.S. official Dennis Ross that the Iranian-backed group Islamic Jihad is trying to provoke conflict with Israel in Gaza.

None of that may look much like a prelude to Iran returning to the negotiating table, except that Iranian officials in the last few days are showing an unexpected and public willingness to talk. Past patterns have shown that Iran never likes engaging from a position of perceived weakness. Talking to U.S. journalists, Foreign Minister Javad Zarif last week floated the idea of a deal that would have the U.S. easing sanctions and Iran agreeing to a tougher nuclear protocol. Then he met with Sen. Rand Paul, R-Ky., a self-appointed U.S. mediator. The New York Times' Farnaz Fassihi also reports on what she regards an intriguing split among Iranian hard-liners on how to deal with Trump between those who have long ruled out any dealings. They include the country's supreme leader, Ali Khamenei, and former President Mahmoud Ahmadinejad, known in Washington for his Holocaust denial and anti-American and anti-Israeli fervor, as well as other conservative clerics and officials close to the Revolutionary Guards who are advocating for negotiations with the U.S. "Mr. Trump is a man of action," Ahmadinejad said. "He is a businessman and therefore he is capable of calculating cost-benefits and making a decision. We say to him, let's calculate the long-term cost-benefit of our two nations and not be short-sighted." He conceded the issues went far beyond the matter of the nuclear agreement and would require "a fundamental discussion." Given both the present perils and the emerging potential, it's time to transform Trump's maximum pressure into diplomatic activity. It's also time to provide a more common front to Iran by taming transatlantic tensions, moderating Washington's partisan bickering and toning down Trumpian tweets so that all parties can better leverage the indisputable economic bite of sanctions into a deal that better contains Iran and avoid war. It really doesn't matter anymore whether you believe Trump never should have withdrawn from President Barack Obama's nuclear deal with Iran in May 2018, and instead should have done more to leverage it with allies and through sanctions for a better deal. It also doesn't matter whether you believe Obama never should have entered such a significant agreement without more effort at bipartisan, congressional approval. Or that U.S. engagement with Iran failed to address the present danger Iran's use of regional proxies, support for terrorists or ballistic missile development. That's water under the bridge. The question now is a larger one: What's the best course to address the largest security challenge in the Middle East, now that the danger of an ISIS caliphate has been wrestled down? Iran's nuclear ambitions had been an accumulating danger, but its Arab and Israeli neighbors all along argued that their more immediate worries were Tehran's destabilizing activities in Lebanon, Syria, Yemen, Iraq and Gaza – which continue.

Even Trump's fiercest critics concede U.S. unilateral sanctions have reduced the resources Iran can invest in malign activities.