To understand the current confrontation between Iran and Israel, it helps to think about three recent phases of Middle East geopolitics.

Phase 1: Before Oct. 7 of last year, Iran was arguably the most isolated power in the region. The Biden administration was growing closer to Saudi Arabia, Iran’s biggest rival for power. Israel, Iran’s longtime enemy, had signed a diplomatic deal during the Trump administration with Bahrain, Morocco and the U.A.E. Iran, for its part, was financing a network of extremist groups such as Hamas and the Houthis.

Together, these developments pointed to the emergence of a broad alliance — among Arab countries, Israel, the U.S. and Western Europe — to check Iranian influence and aggression.

Phase 2: Hamas’s Oct. 7 attack on Israel scrambled the situation. Israel’s massive military response focused global attention on the plight of Palestinians — a subject that tends to isolate Israel. Arab leaders condemned Israel, while the U.S. and other countries pressured Israeli leaders to reduce suffering in Gaza and devise an end to the war.

The anti-Iran coalition seemed to be fraying.

Phase 3: The latest phase began last week, as Iran prepared to fire missiles and drones at Israel in retaliation for Israel’s April 1 assassination of Iranian military commanders who work with groups like Hamas. This retaliation would become Iran’s first direct attack on Israel. And the anti-Iran coalition reassembled to repel it.

U.S. officials worked closely with Israel to intercept the missiles, as my colleague Peter Baker reported. British and French forces participated, too. Arab countries shared intelligence. Jordan went so far as to shoot down some drones itself. When President Biden commented on the attack’s failure, he did so while sitting next to the prime minister of Iraq, which is home to a missile battery the U.S. had used during the operation.

Even though Iran fired more than 300 drones and missiles at Israel, the joint response enabled Israel to avoid a single civilian death. John Kirby, a Biden aide, summarized the result as being “a stronger Israel, a weaker Iran, a more unified alliance.”

A new phase now?

The question now is how Israel will respond to Iran. Israeli officials have said they must do so to exact a price that will deter future Iranian attacks.

From Israel’s perspective, Iran is already the aggressor: Its official policy is to seek the destruction of Israel, and Iran-backed groups — like Hamas, Hezbollah and the Houthis — regularly attack Israelis. Israel has responded with covert assassinations of Iranian officials who lead this effort, such as the April 1 strike in Syria. After any future assassination, Israel does not want to face a new Iranian missile barrage.