For more than a year, Iran has been building permanent military bases in Syria close to the Israeli border. Since the first reports of this activity were published in November 2017, Israel has made it clear that it would not permit the Iranians to do so because the threat to Israel is far too great.

From these bases, Iran has been operating drones over Israeli airspace. It has dozens, perhaps hundreds, of its Iranian Revolutionary Guard Corps troops operating from those bases.

On at least four occasions — from February 10 to April 17 — Israel has attacked those bases. Israel’s April 9 strike on the “T-4” base near Homs killed about seven Iranian officials or soldiers, including an IRGC colonel commanding the drone operations.

Though several Iranian leaders have spoken in terms of an imminent war with Israel, Iran has not even conducted any small attacks in response to Israel’s attacks on its bases. Why?

Some, including the analysts at the Middle East Media Research Institute (MEMRI), assert that by its military strikes on Iranian bases, Israel is asserting that it is ready for an all-out war with Iran. That is consistent with statements by Israeli Prime Minister Benyamin Netanyahu. He said, “We hear the threats from Iran, and the IDF and security forces are prepared for every possible Iranian move. We will fight whoever tries to harm us. We will not shy away from action against those who threaten our security. They will pay a heavy price.”

Many Iranian government-controlled newspapers and lower-level Iranian officials, such as Gen. Salami, deputy commander of the IRGC, have responded in kind, warning that Israeli airbases are within range of Iranian missiles which are ready to be launched at any provocation.

April 18, the day Israel celebrated the 70th anniversary of its independence, was also Iran’s “army day.” Then, the commander of Iran’s ground forces in Syria, IRGC Brigadier General Kiumars Heidari, said that Israel can no longer threaten Iran.

But, as MEMRI reports, Iran’s “supreme leader” Ayatollah Khamenei and his principal operative, IRGC commander Ali Jafari, have remained silent about any counterattack against the Israelis. Both are usually very vocal with threats against Israel, which they call “the little Satan.” (“Big Satan, of course, is us.)

Regardless of how ready they may be, the Israelis clearly don’t want a general war with Iran. In such a conflict, even if Iran hasn’t yet developed nuclear weapons, Israel would suffer masses of casualties. Iran’s proxy in Lebanon, the terrorist network Hizballah, has thousands of short-range rockets and long-range missiles that would be fired at Israel. Israel’s missile defense systems — “Iron Dome,” “Magic Wand,” and “Arrow” — are designed to shoot down incoming rockets and missiles, but they can be overcome by mass salvos of incoming missiles and rockets.

Hizballah would also try to capture and hold — even for a short time — Israeli towns on the Lebanese border. (I use the term “Hizballah” rather than the bowdlerized “Hezbollah” because that is the name it calls itself.)

Iran, too, would suffer enormously. Israel’s air force and its offensive missile capabilities could inflict tremendous numbers of casualties and would probably destroy large elements of the Iranian government. (The ayatollahs, like Kim Jong Un, are not eager to die for their cause.)

The likely damage that Iran would suffer doesn’t comprise the reason that it hasn’t counter-attacked Israel. There are three reasons it hasn’t, at least yet.

First and foremost is that Iran doesn’t want to give President Trump another reason to cancel Obama’s nuclear weapons deal with the ayatollahs, which he is likely to do around May 12. Our European allies — Britain, France, and Germany — are pressuring Trump to give them more time to push Iran for greater concessions under the deal, which it will never grant. China and Russia, also parties to the deal, are also pressuring Trump to not revoke the deal.

Second, the Iranians probably haven’t obtained Russian support for any attack on Israel. So far, Russia has turned a blind eye to Israeli attacks on Syrian-Iranian targets despite its alliance with Iran and Turkey to keep Assad in power. Though Russian consent won’t be a sine qua non of any counterattack, Israel’s relations with the Putin regime are generally good and Russia may be telling Iran to hold off on any action until Trump makes his decision on the Obama nuke deal, in which Russia has a great investment.

Third, as MEMRI reports, it’s entirely unclear that Iran has any popular support for an attack on Israel which clearly would primarily be part of its adventurism in Syria. Credible reports of anti-regime demonstrations in Iran, based principally on its Syria campaign, are becoming public irregularly.

All of this is not to say that a general war between Israel and Iran won’t erupt at any time. More likely are post-May Iranian counterattacks on Israeli military or civilian targets. Restraint will characterize any Israeli responding attacks unless Iran orders Hizballah to launch its rockets and missiles at Israeli civilians.

In that event, Israel would be faced with a three-front war in Syria, Lebanon and Iran.

As militarily powerful as Israel is, such a conflict would be extremely difficult for it to win. As my pal Chuck Freilich, former Israeli deputy national security advisor, explains in his brilliant new book, Israeli National Security, Israel is even more sensitive to casualties than we are, and the prospect of hundreds or thousands of civilians dying from Hizballah and Iranian missile attacks is an even more powerful political disincentive that directly affects its warfighting capabilities. The international opprobrium that would descend on Israel if it launched any direct attacks on Lebanon or Iran is another powerful cause for restraint.

Iran has been at war with Israel since the ayatollahs came to power in 1979. So far, it has chosen to ignite proxy wars such as the last Israel-Hizballah war in 2006. Another such war — confined to Israel and Lebanon — is the most likely outcome this year.

Such a war will be immensely bloody for both sides. In the 2006 war, Israeli forces were authorized to enter Lebanon as far as the Litani River, about 25 miles north of the Israeli border. Since then, Hizballah’s capabilities have increased enormously, with its long-range missiles able to strike Israel from far north of the river.

Any Israeli invasion of Lebanon would be enormously costly in military and civilian lives. If, for example, Hizballah were successful in capturing northern Israeli towns such as Kiriat Shmona, on the Lebanese border before it was evacuated, it could result in an Hizballah massacre of civilians.

Will such a war erupt in the next two or three months? Only Iran knows for sure.