In May 1967, I left the U.S. Information Agency in Washington, where I had been learning Vietnamese, and went to the Associated Press in New York. The editors there, many experienced in the Middle East, sensed tensions building toward war there better than anyone in Washington, which focused obsessively on Vietnam. If U.S. officials knew, they did not say.

Actually, tensions had been growing at least since 1964, especially as Israel began an ambitious water project. Syria begged for Soviet arms, and Moscow delivered. After Israeli Dassaults downed six Syrian MiGs in an April dogfight, Damascus falsely claimed that Israel was massing on Syria’s border, and the Soviets backed up the Syrian lie. This pushed Nasser to mobilize for war, which decided Israel to pre-empt on June 5, launching the Six-Day War.

One feels the same tension today, a sense that this has been building inevitably for several years and is now pushed over the edge into a U.S.-Iran war. At a certain point, escalation escapes human agency, and events feed on themselves into war. With neither side showing any willingness to back down, we are rapidly approaching that point.

Could things have gone differently? Possibly. The 2015 Iran nuclear deal, imperfect as it may have been, was starting to calm things. For example, in 2016, Iran held two U.S. Navy boats overnight (apparently they ran out of fuel), but personal contact between Secretary of State Kerry and his Iranian counterpart, who had just concluded the deal, ended the tension quickly and smoothly. Useful, these diplomatic contacts.

Donald Trump always scorned the deal and claimed he could do a lot better. His heavy-handed threats got nowhere, and in mid-2018 he tore up the deal. The other parties to the agreement tried to keep it alive, but Iran began refining more uranium.

Major General Qasem Suleimani, in charge of Iranian operations and clients in Iraq and Syria, long and deeply hated America. Described as the second most powerful figure in Tehran, after the Ayatollah, he had political ambitions. Washington’s charge that he was returning from Syria to prepare strikes on U.S. posts in Iraq — including the embassy — is credible.

Congress is a helpless spectator. Some may try to invoke the toothless 1973 War Powers Act, but the Trump White House claims the president has the right and duty to prevent attacks against the United States, which are indeed likely.

The war raises many questions. Who provided the intel of where and when Suleimani would be? Were they strictly U.S. sources (from satellites and intercepts), or did they draw on Saudi and/or Israeli help? It was awfully accurate, indicating major U.S. capabilities. Good. Where did the U.S. drone launch from? A carrier in the Persian Gulf? Qatar? Saudi?

Was this an assasination? In 1943, U.S. codebreakers learned that Admiral Yamamoto would be flying between islands and sent three P-38s to shoot his plane down. Was that murder or just part of a war? Did it impact the length or course of the war? Probably not. It was revenge for Pearl Harbor. Ironically, Yamamoto knew and liked America and had opposed the war.

In April 1986, a Libyan bomb (possibly planted by Palestinians) ripped apart a Berlin bar frequented by American soldiers. In retaliation, the U.S. bombed Libya, possibly aiming for Qaddafi personally. In retaliation for that, in December 1988, a Libyan bomb downed Pan Am 103 over Scotland, killing 270. That could have been grounds for war, but it took over a year to pinpoint blame. These things tend to grow, but Libya backed off and paid an indemnity.

Iran is unlikely to back off. As before, it will avoid outright conventional war but will practice asymmetrical attacks on vulnerable targets. Get ready for cyber attacks. Fearing U.S. nukes, Iran will probably not prepare another 9/11. Iran has already hit Saudi oil targets with precision. Tankers in the Persian Gulf are likely targets, pushing the U.S. to destroy Iran’s navy.

How will it end? The American public is fed up with Mideast wars, and Trump has promised to end them, easier said than done. U.S. airpower can take out most Iranian military targets, but that would not produce the regime change Washington desires. That would require ground forces — at least a quarter million — amid Iranian resistance, which would be much tougher than in Iraq, more like Afghanistan.

U.S. armed forces, now totaling a trim 1.4 million, could not staff an Iranian occupation. That would require a major military expansion and a draft. Would Congress enact a new conscription law? Doubtful. Iran’s oilfields are concentrated in its southwest, in Khuzestan Province, home to many non-Persians. This could give Trump the chance to “keep the oil,” which he advocated for Iraq. This financial transaction would be a dreadful strategic move.