If the Tehran-Washington war of words gives way to conventional war, the Golan Heights might be the battlefield.

Over the weekend President Trump exchanged strong words with Iranian officials. Secretary of State Pompeo, meanwhile, encouraged Iranians to resist their regime. Tehran, for its part, threatened to shut down the Strait of Hormuz, through which some 20% of the world’s oil passesIt’s an empty threat. Such a move would lead to a direct confrontation with America, and Tehran’s modus operandi has long been to instigate proxy wars instead.

One of those proxy wars is raging on the Syrian side of the Golan Heights, an area President Bashar al-Assad mostly ignored while fighting for his regime’s survival elsewhere in the country, but where now, aided by Russia and Iran, he’s completing his victory.

Mr. al-Assad’s move on the Golan is worrisome for Israel. On Monday the IDF deployed, for the first time, its David’s Sling defensive system, intercepting two half-ton bombs that appeared aimed deep into its territory.

On Tuesday a Syrian army Russian-made Sukhoi plane was downed by an Israeli Patriot missile, after wandering a mile into Israel’s airspace.

Mostly, Israel is concerned that as Mr. al-Assad’s army takes over, it will give Iran a foothold on its border.

Iran has long used proxy militias — Shiite fighters from Lebanon, Iraq, Afghanistan and elsewhere — to prop up Mr. al-Assad’s army. Now, “some of the forces that are wearing Syrian military uniforms are actually not Syrians, but forces arranged by Iran that were sent to fight for the Syrians,” a former Israeli military official, Yossi Kuperwasser, now with the Jerusalem Center for Public Affairs, told reporters Monday.

Iran, in other words, controls much of Mr. al-Assad’s army, and Israel won’t let it set up camp on its borde. But whether Jerusalem can stop it depends in part on Russia. Moscow intervened to save Mr. al-Assad but is clearly now in over its head.

So on Monday President Putin dispatched Foreign Minister Lavrov and his army chief of staff, General Gerasimov, to Jerusalem for an “urgent” meeting with Prime Minister Netanyahu and aides. Maps were shown, intelligence was exchanged, and the Russians reportedly offered to keep Iran some 60 miles away from Israel.

Deal? As Israel’s ambassador, Danny Danon, told me Tuesday, “We have policies; we don’t have a deal.”

Israel demands no presence of Iranian or proxies anywhere in Syria; no missiles or drones that can hit the country’s centers; no advanced antiaircraft weapons; no Iranian military bases; closure of the Syrian borders where Iranians come into the country.

As the incident on Tuesday showed, though, Russia can deliver on none of those demands. Mr. Putin has much less control over the various Syrian players than he and President Trump seemed to suggest at their recent press conference.

The Israelis know it, but they must coordinate with Moscow to prevent any confrontation with Russian planes. They don’t want to add Russia to the growing list of adversaries they must confront to keep Iran from taking over Syria and creating another, even-more-formidable threat on the Israeli border.

In Washington, meanwhile, Mr. Trump’s aides are, as on all fronts, divided.

Sources familiar with the administration’s internal debate tell me the president and Pentagon officials have accepted President Obama’s premise that American troops in Syria are there just to fight ISIS. After the Islamic State’s near-complete demise, why keep them there as sitting ducks? Others argue that as we confront Iran’s regional aggression, removing all forces from Syria would amount to raising a white flag.

Meanwhile, a Capitol Hill initiative to recognize Israel’s sovereignty over the Golan Heights, which it has controlled since 1973 and annexed in 1981, is gaining momentum.

Traditionalists warn such recognition of reality will only exacerbate tensions, but as a senior Republican congressional staffer told me, “Fiction can be useful in diplomacy, but once it stops being useful there’s no reason to keep it up.”

Early on in the Syria war, Mr. Obama colluded with Mr. Putin and facilitated Russian and Iranian dominance there. Now Washington aspires to push back against expansionist Iran, which will sooner wage its battles in Syria than closer to home.

The least we can do is give Israel all rhetorical, diplomatic and military help to fight this battle.

This column first appeared in the New York Post.