Following the terrorist attacks launched by Hamas in 2023, Israel rapidly initiated large-scale military operations in the Gaza Strip with the declared objective of eliminating Hamas. The ensuing military campaign led to a rising number of civilian casualties and a worsening humanitarian crisis. These developments exerted growing pressure on U.S. domestic politics during an election year, adversely affected the Democratic Party’s electoral prospects, and undermined the Biden administration’s efforts to advance its “New Middle East Strategy.” From February 2024, to ease domestic public opinion pressure while mitigating the negative impact on its regional strategy, the Biden administration sought to restrain Israel’s military operations in Gaza through various U.S.-Israel institutional consultation mechanisms, issuing warnings and exerting pressure, while also adopting punitive measures in the areas of arms supply and diplomacy. However, these efforts failed to produce tangible results, as Israel continued its military campaign in Gaza. This article argues that the Biden administration’s restraint of Israel constitutes a failed attempt at alliance restraint. The failure stems from inadequate enforcement capacity, but more fundamentally, it reflects a lack of genuine political will. In the view of U.S. strategic circles, Israel’s military operation in Gaza serves the advancement of top-priority objectives on the U.S. foreign policy agenda. President Trump, who returned to the White House in January 2025, did not consider constraining Israel’s Gaza operations as a policy option for addressing the Gaza crisis. Since there exist some differences between U.S. and Israel on some governance issues in post-conflict Gaza, it is still possible for Trump 2.0 to apply “alliance restraint” to U.S. policy towards Israel.