A group of prominent Democrats in the House of Representatives has urged President Joe Biden’s administration to end the “lack of U.S. enforcement” of human rights law as the country continues its military support for Israel — suggesting an Israeli “culture of impunity” is driving bloodshed in the Palestinian territories and in Lebanon, which Israel invaded earlier this week.

“The failure of the United States to consistently apply our own laws … actively endangers the lives of US citizens,” Rep. Jim McGovern (D-Mass.) and four colleagues argue in a letter they sent the Pentagon and State Department this week and exclusively shared with HuffPost.

Israeli forces have killed several Americans in the occupied West Bank, most recently Aysenur Ezgi Eygi on Sept. 6, they note. They also cite “credible reports” of Israeli officials subjecting detained Palestinians to torture, sexual abuse and mistreatment, as well as Israeli troops shooting civilians carrying white flags during their ongoing military campaign in Gaza.

Though small, the Democratic group includes heavyweights: McGovern is the top Democrat on the powerful House Rules Committee, and his co-signatories include Reps. Barbara Lee (Calif.), Mark Pocan (Wis.) and Betty McCollum (Minn.), key players on the House Appropriations Committee that oversees government funding, as well as Rep. Joaquin Castro (Texas) of the House Foreign Affairs Committee.

Specifically, the legislators highlight the Leahy Law, which bars U.S. funding for foreign military forces that are accused of serious rights abuses.

“When it functions properly, the Leahy Law serves two crucial purposes: it prevents U.S. complicity in gross violations of human rights, and it deters violations by incentivizing foreign governments to hold perpetrators accountable,” reads the letter, which lawmakers sent Monday. “However, the Leahy Law can only serve these purposes when it is enforced.”

Washington has never cited the decades-old law to cut off aid to an Israeli military unit. Earlier this year, the Biden administration announced that though U.S. officials had recommended multiple Israeli military units be disqualified from American assistance, U.S. Secretary of State Antony Blinken believed Israel had taken steps to address alleged misconduct — and so would not blacklist the units.

Charles Blaha, a former State Department official deeply involved in implementing the Leahy Law, has publicly said he believes the government does not fairly apply it to Israel.

“Information that for any other country would without question result in ineligibility [for U.S.-funded assistance] is insufficient for Israeli security force units,” Blaha wrote earlier this year. “Political considerations, including the possibility of criticism from a foreign government, are not relevant to Leahy law eligibility decisions. But in actual practice, some [U.S. officials] ... include concern about criticism from the government of Israel as a factor in determining whether a unit is ineligible and deciding which cases to send to higher levels for action.”

The new congressional letter cites Blaha’s testimony.

State Department spokespeople deny that the U.S. gives Israel special treatment in terms of applying laws governing military support. Israel says its military respects U.S. and international law and investigates accusations of behavior that may breach those standards.

Yet the letter notes that the U.S. gives Israel significant leeway in determining how to punish perpetrators. Watchdog groups say Israel’s response to illegal behavior against Palestinians by its personnel frequently amounts to a slap on the wrist, while the Israeli government often aggressively denies claims of misconduct, requiring serious pressure to even investigate them.

The U.S. is Israel’s chief military backer by far, sending it more than $3.5 billion in annual military aid — and has sent additional billions since the Oct. 7, 2023, attack by the Palestinian militant group Hamas that killed nearly 1,200 people and led to some 240 being taken hostage, including Americans. This policy generally has bipartisan support as boosting an ally in the face of regional forces wary of the U.S., from Hamas to Lebanese militia Hezbollah and Iran, which supports both those groups.

Still, as the toll of Israel’s post-Oct. 7 military operations has risen — now including more than 41,500 Palestinians and more than 2,000 Lebanese — more and more observers say the policy needs to be reconsidered. The legislators who signed the new letter call themselves “long-time friends and allies of Israel” who believe in its right to self-defense against Hamas, Hezbollah and others.

The Leahy Law does not cover all forms of U.S. military support for Israel or all forms of potential violations by foreign governments of the laws of war and American law. But tighter implementation of the law could send a firm signal to the Israeli government and increase the chance that the U.S. and its allies pressure Israel more broadly to do more to avoid committing war crimes, advocates of the idea believe.

Hopes of a different approach are growing as concerns swell about Israel’s actions in Lebanon, where it is repeating many of the tactics that devastated Gaza: issuing sweeping evacuation orders that international law experts say breach standards for protecting civilians; striking densely populated areas in seemingly disproportionate attacks; and striking protected groups like medical workers.

Though the Biden administration has mostly declined to reconsider its pipeline of weapons for Israel, it acknowledged in a May report that “it is reasonable to assess that [U.S.-provided] defense articles ... have been used by Israeli security forces since October 7 in instances inconsistent with its [international law] obligations or with established best practices for mitigating civilian harm.”

“A failure to apply the law to Israel has sent the [Prime Minister Benjamin] Netanyahu government a message of impunity and undermined the Biden administration’s stated objective of securing a cease-fire,” argued John Ramming Chappell of the Center for Civilians in Conflict advocacy group, describing “a continuation of patterns from Gaza” in Lebanon with full support from the U.S.

Chappell said the U.S. could hold Israel accountable by applying the Leahy Law and other legislation like the Foreign Assistance Act, whose Section 620I prohibits American military backing for countries that bar the distribution of American-provided humanitarian aid. Lawmakers, current and former U.S. officials and independent analysts say the Biden administration’s policy appears to violate that statute.

Stacy Gilbert, a veteran State Department aid official who quit over Biden’s Gaza policy in May, previously told HuffPost that the administration is “twisting the facts” on Israel’s handling of supplies for Palestinians.

“It is evident that Israeli security forces benefit from a double standard here,” Chappell said.

Pushback to Biden’s Israel policy is quietly building on Capitol Hill and is expected to come to a head publicly in mid-November, when Sen. Bernie Sanders (I-Vt.) is planning a Senate vote on Biden’s plan to send Israel more than $20 billion in additional weapons.

Read the letter from lawmakers below: