Israeli Prime Minister Benjamin Netanyahu had to cut short his visit to Washington after a barrage of rockets from Gaza prompted Israeli airstrikes in response on Monday. But on the flight back to Jerusalem, officials were optimistic about the state of U.S.-Israel relations.

One senior Israeli official on the plane, who spoke on the condition of anonymity to freely discuss bilateral relations, pointed to the Trump administration’s recognition of the occupied Golan Heights as evidence of a new attitude in Washington.

The recognition of the Golan Heights showed that occupied territory can be held on to and occupying territory gained from a defensive war can be justified, the official told reporters.

The remark echoed comments by Netanyahu at a news conference with President Trump on Monday. “Israel won the Golan Heights in a just war of self-defense,” the Israeli leader said.

To some observers, that justification would go directly against the traditions of U.S. foreign policy — indeed, one that would defy the norms of international relations in the post-World War II era.

The implications could be considerable, not only with regard to Israel and the Palestinian territories but also for many other parts of the world where land has been illegally occupied after conflict.

During an interview in Beirut this week, Secretary of State Mike Pompeo was asked whether there was no double standard in the United States imposing sanctions on Russia for the 2014 annexation of Ukraine’s Crimean Peninsula and recognizing Israeli control of the Golan Heights.

“Not at all. What the President did with the Golan Heights is recognize the reality on the ground and the security situation necessary for the protection of the Israeli state. It’s that — it’s that simple,” Pompeo said in an interview with Sky News.

A State Department spokeswoman said Tuesday that there had been no shift in U.S. policy and that the circumstances surrounding Crimea and the Golan Heights were vastly different.

“Israel gained control of the Golan through its legitimate response to Syrian aggression aimed at Israel’s destruction,” the spokeswoman said, speaking on background because of department rules. “Russia has occupied Crimea despite the fact that it has recognized Crimea as part of Ukraine in bilateral agreements, and despite its international obligations and commitments, including core OSCE [Organization for Security and Cooperation in Europe] principles.”

“The U.S. policy continues to be that no country can change the borders of another by force,” the spokeswoman added.

The Golan Heights, a high plateau that sits on the border between Israel and Syria, was part of Syria until Israeli forces seized it during the Six-Day War of 1967. In 1981, Israel effectively formalized its annexation.

The Six-Day War is widely considered a military triumph for Israel, with the young nation’s army decisively beating the armies of three Arab nations: Egypt in the south, Jordan in the east and Syria in the north. The war began after Israel launched a preemptive strike following extensive military mobilization by its neighbors.

In the past, Israeli prime ministers, including Netanyahu, have seen the Golan as a potential part of a peace agreement with the Syrian government. Israel returned the Sinai Peninsula, also captured during the Six-Day War, to Egypt in 1979 as part of a peace agreement.

However, the ongoing Syrian war and the associated threat of Iranian forces and Lebanon’s Hezbollah militia in Syria — working to back up President Bashar al-Assad’s government — have led to support in Israel for a permanent annexation of the Golan.

Since the end of World War II, the international community has condemned instances of countries using conflict to seize land or change borders. The U.N. Charter, signed in 1945, mandated that all members must “refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state.”

After Israel formally took control of the Golan Heights in 1981, the U.N. Security Council called the move “null and void and without international legal effect.”

The 2014 Russian annexation of Crimea is the most high-profile example of a country using conflict to extend its borders, though academics have pointed to China’s actions in the South China Sea as another example. Ongoing conflicts in Syria, Yemen and elsewhere have raised the possibility of more borders being redrawn through conflict.

Before boarding his plane at Joint Base Andrews in Maryland on Monday, Netanyahu accused reporters of not recognizing the importance of Trump’s decision on the Golan Heights.

“Why are you asking about Gaza? What about what I achieved with Trump: Why aren’t you covering that?” the prime minister said.

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