UNITED NATIONS — Israel’s 50-day war with Palestinian militants in Gaza was a “game changer” that persuaded the Palestinian president, Mahmoud Abbas, to shelve the already moribund American-sponsored peace talks and decide to join the International Criminal Court, even if that meant defying the United States, a senior Palestinian leader said Tuesday.

“Because enough is enough, and what has the U.S. done for us?” Hanan Ashrawi, a member of the executive committee of the Palestine Liberation Organization, said in an interview during a visit to the United Nations.

Dr. Ashrawi’s visit was part of a new strategy by Mr. Abbas to put international pressure on Israel and to lift his government’s standing among Palestinians in the aftermath of the Gaza war. That strategy involves bringing a Security Council resolution this month that would demand an end to Israeli occupation within three years — a bid that Dr. Ashrawi said the United States was likely to block — as well as acceding to the treaty that created the International Criminal Court.

She was to meet with the American ambassador to the United Nations, Samantha Power, late Tuesday before heading to Washington, she said. The United States Mission declined to immediately comment.