UNITED NATIONS—If the Palestinian Authority succeeds in winning even an incremental upgrade of its status at the U.N, it could subject Israel's military to international courts for actions in Palestinian territory—as well as allow Palestinian control of its Israeli-patrolled air space and national waters off Gaza.

Palestinian Authority President Mahmoud Abbas said Friday he would seek full U.N. membership through the Security Council. If the U.S. vetoes that effort, as it has vowed to do, the Palestinians have a second option for membership: go to the General Assembly.

Francis Boyle, a legal adviser to Mr. Abbas, told The Wall Street Journal that he has advised the Palestinian president to take this step, which is made possible through a resolution, known as Uniting for Peace, that was introduced by the U.S. in 1950 to circumvent repeated Soviet vetoes of Security Council measures to help South Korea battle the North.

To succeed, the Palestinians would have to convince two-thirds of the voting Assembly that Palestinian membership would be a response to an existing "threat to peace, breach of the peace or an act of aggression" from Israel.

The U.S. and Israel say a U.N. vote would itself threaten peace.

The Palestinians have a third option: Seek an upgrade from permanent-observer mission to a nonmember, permanent observer state in the Assembly. That route has fewer roadblocks, since no country holds a veto in the Assembly, and diplomats say the Palestinians have more than the required 97-vote simple majority.

Such an upgrade could be more than symbolic, potentially altering the political equation between the Palestinians and Israel.

As an observer state, Palestine could participate in Assembly debates, but couldn't vote, sponsor resolutions or field candidates for Assembly committees. But it could accede to treaties and join specialized U.N. agencies, such as the International Civil Aviation Organization, the Law of the Sea Treaty, and the International Criminal Court, officials said.

Switzerland joined the ICAO in 1947 when it was still an observer state before becoming a U.N. member in 2002.

Denis Changnon, an ICAO spokesman, said the treaty gives members full sovereign rights over air space, a contentious issue with Israel, which currently controls the air space above the West Bank and Gaza. The Palestinians could bring claims of violation of its air space to the International Court of Justice.

If the Palestinians accede to the Law of the Sea Treaty, they would gain legal control of national waters off Gaza—where they are currently under an Israeli naval blockade.

Under the treaty, the Palestinians could challenge the blockade at the International Court of Justice. They could also claim rights to an offshore natural-gas field now claimed by Israel.

Even more troubling for Israel and the U.S. would be Palestinian membership in the International Criminal Court. Ambassador Christian Wenaweser, president of the ICC Assembly of State Parties, said in an interview that a Palestinian observer state could join the ICC and ask the court to investigate any alleged war crimes and other charges against Israel committed on Palestinian territory after July 2002. including Israel's 2008-09 assault on the Gaza Strip.