Donald Trump claims to have mastered the Art of the Deal, but he has just given us a master class in negotiating incompetence. I would love to see an Iranian government that no longer represses its people, menaces its neighbors, or can build a nuclear weapon. Trump has set back all of these efforts. His cabinet of sycophants offered little resistance as he naively bombed first and faced reality later.

Trump is reviewing and tinkering with a proposed memorandum of understanding (MOU) drafted by American and Iranian diplomats with the aid of Pakistan and Qatar. It would continue the current ceasefire for 60 days while a more permanent peace accord is negotiated. The precise contours of this preliminary agreement are not known, but its gist seems clear – and is a profound embarrassment for Trump. His unprovoked war of choice has accomplished all of nothing. A new approach is urgently needed.

The best way to assess Trump’s quandary is by comparing it with what a less bellicose approach might have secured. Trump says he wants to deny Iran a nuclear weapon, but Tehran has repeatedly disavowed that goal. Rather, the real issue, given broad distrust of Iran’s clerical leaders, is how to prohibit them from obtaining the means to build a bomb.

That’s what Barack Obama’s 2015 deal with the Iranians did. The joint comprehensive plan of action, or JCPOA, curtailed their nuclear program subject to intrusive international inspections. It contained sunset clauses, but they could have been extended by further agreement. Yet Trump withdrew from that accord in 2018, vowing to pressure Iran into a better deal. It didn’t work.

The JCPOA had allowed Iran to enrich uranium to only a minimal 3.67% – a far cry from the 90% needed for a nuclear weapon. Iran sent 11 tonnes of uranium that had been modestly enriched above the lower level to Russia, leaving it no path to build a bomb.

Trump’s repudiation of the JCPOA removed these limits. That enabled Iran to produce nearly half a tonne of highly enriched uranium at a purity of 60%. That is a short hop from the enrichment needed for a bomb.

Trump is now back at square one. He is trying to persuade Iran again to limit its enrichment program and to export or dilute its enriched uranium – in other words, to do what it agreed to do with Obama. That was the subject of negotiations in February of this year, but Trump abruptly ended those talks in favor of war.

Trump’s hope was to bomb and sanction Iran into submission. On the urging of the Israeli prime minister, Benjamin Netanyahu, American and Israeli bombers tried to decapitate the regime, hoping for a more pliant successor or even a popular uprising. At one point, Trump had the hubris to demand “unconditional surrender”.

But if anything, the killing of Iranian leaders, including former supreme leader Ayatollah Ali Khamenei, enhanced the power of hardliners associated with the Islamic Revolutionary Guards Corps. And it was always wishful thinking that the Iranian dictatorship, which had survived years of sanctions and had slaughtered at least 7,000 anti-government protesters in January, would be more concerned about the welfare of the Iranian people under bombardment than in retaining power. Nor would the Iranian people be eager to take to the streets again to face more bloodshed at a time when their immediate concern was avoiding death from the sky.

Trump had no plan B. He claimed to have destroyed Iran’s missile and drone capacity. Instead, he substantially depleted US arms stockpiles while leaving most of Iran’s arsenal intact and its ability to wreak havoc considerable.

Trump also turned the strait of Hormuz from a theoretical into an actual weapon, one arguably more powerful than a nuclear bomb because it is more usable. With one fifth of the world’s oil and liquified natural gas supply passing through the strait before the war (as well as fertilizer, sulfur and helium), the economic consequence of closing the strait are far-reaching. Iran has compounded the effect by attacking oil and gas facilities in the Gulf Arab states.

The Iranians have Trump over a barrel. He pretends not to care about the November midterm elections, but everyone sees that the mounting cost of gasoline and its inflationary pressure mean that, despite their gerrymandering, the Republicans are likely to face a shellacking.

Trump is thus fixated on reopening the strait so that oil and gas deliveries can resume. Meanwhile, he is punting on the key nuclear questions – the ostensible reason for this counterproductive war. In the MOU, Iran reportedly will again disavow its intention to build a nuclear bomb, but the key issue of denying it the means – of limiting enrichment and neutralizing its highly enriched uranium – will be kicked down the road for later discussion.

Other issues cited by Trump as reasons for war, such as Iran’s ballistic missile program and its support for regional armed groups, are apparently nowhere to be found in the proposed preliminary accord. In other words, the MOU will only return us to the February status quo, before the strait of Hormuz was even in play. The Trump-Netanyahu bombing campaign was for naught.

Indeed, US negotiators are now worse off. Knowing that Trump is desperate to get the oil flowing again, Tehran has upped the ante. Reflecting distrust of Trump, the Iranians reportedly want their frozen assets released and at least some sanctions lifted before nuclear negotiations begin. They are also said to be seeking an “investment fund” to help with postwar reconstruction – in amounts far larger than those that Trump had vehemently criticized Obama for allowing. Trump may try to fudge the matter by allowing Qatar to hand over funds instead.

The MOU is likely to require that passage through the strait be “unrestricted” while negotiations proceed, and Trump has gone so far as to threaten to bomb Oman, a US ally, should it join Iran to control the strait. Iran thus will probably be forced to eschew the imposition of “tolls” but may toy with surrogates such as an “environmental fee”. None of that was on the table in February before Trump’s war of choice.

Tehran is also insisting that a new 60-day ceasefire extend to Israel’s military operations in Lebanon. That demand is understandable, because in the name of fighting Hezbollah, an Iranian ally, Israel has forced 1 million people from their homes in southern Lebanon – one fifth of the country’s population. As the possible MOU became public, Israel intensified its attacks in Lebanon and for the first time in two decades advanced above the Litani River.

As in Gaza, Israel has breached even the current ceasefire, periodically dropping bombs as it reduces villages in southern Lebanon to rubble. Netanyahu has also told Trump he reserves the right to respond to “threats” in Lebanon, a formula that Israeli troops in Gaza have exploited to continue killing Palestinians. As in Gaza, Israel is also likely to insist that a ceasefire not include withdrawal from the vast swathes of Lebanese territory that it now occupies.

There are lessons to be learned from this debacle. First, Trump should definitively repudiate Netanyahu’s preference for endless armed conflict. If Israel’s far-right government can be said to have a long-term strategy, it is to eschew negotiation for war, to bomb and bomb and, when the other side recovers, bomb some more. “Mowing the grass” is how this callous approach is described.

Trump, who prides himself on being a deal-maker, should prioritize negotiation and drop his saber-rattling, such as his blatantly illegal (and thinly disguised nuclear) threat to destroy Iran’s civilization. While negotiators inevitably deploy carrots and sticks, Trump should make military force a last resort, to be used only in the narrow circumstances permitted by the United Nations charter. That is the right way to proceed as a matter of not only international law but also military practicality now that the Iranian military, equipped only with drones, sea mines and speedboats, has shown itself capable of imposing enormous costs on the world’s most powerful country, not to mention the global economy.

Iranian officials are known to be tough negotiators, but Trump has plenty of leverage without resorting to another war of aggression. Between Iran’s frozen assets and the many sanctions imposed on the country, Trump can engage in an incremental give and take that should be capable of achieving an acceptable solution.

As for what that solution should be, the focus should be back where it started – on denying Iran the means to secure a nuclear weapon. That requires no longer insisting on the dealbreaker demand that Iran forsake the ability to enrich uranium to modest levels, as all other governments are allowed under the Treaty on the Non-Proliferation of Nuclear Weapons.

Rather, pairing modest enrichment with intrusive international inspections should suffice to prevent secret bomb development. Trump may also need to accept creative solutions to neutralize Iran’s cache of highly enriched uranium – some combination of dilution, monitoring and export – as he has suggested he might.

Most importantly, despite his inclinations, Trump must for once put the nation’s (and world’s) interest above his own. Trump’s ability to deny the facts and spin reality is impressive, but even he will have a hard time selling this debacle as a victory. And Tehran may not give him a face-saving way out. We must insist that he accept a deal anyway, even if it reveals the Master Deal-maker to be a Master Bungler.

• Kenneth Roth is a Guardian US columnist, visiting professor at Princeton’s School of Public and International Affairs, and former executive director of Human Rights Watch. He is the author of Righting Wrongs: Three Decades on the Front Lines Battling Abusive Governments