But Sullivan wasn’t calling to complain. To Van Hollen’s surprise, the administration was open to converting the amendment — which would have applied only to new funding — into a memo with the force of law, meaning it would apply to all U.S. military aid and stay in effect even if the president’s supplemental bill didn’t make it through the House.

Biden issued the order last week and it won the approval of most Senate progressives. The chamber passed the supplemental on Tuesday.

“There’s no requirement right now that if you want to receive American weapons, you have to facilitate the delivery of humanitarian assistance in conflict zones where those weapons are being used,” said Van Hollen. He called the new policy “a very important tool to both pressure recipient countries but also to pressure the Biden administration to take action to insist on what the [policy’s] promise requires.”

White House officials have stressed that the directive didn’t impose new standards for military aid and that the administration had already been following the underlying policy. NSC spokesperson Adrienne Watson said the directive was not being issued because the administration believed a country was violating the standards. “If we did, you’d have heard about it long ago — and seen the consequences,” she said.

But the fact that Biden took the step still underscores what type of political pressures he responds to. For months, the White House has been under an intense public barrage to more fully address humanitarian issues in Gaza and Israel’s aggressive conduct of the war.

The administration responded by publicly calling for more aid to be sent into Gaza and with a more fulsome pushback to proposed military operations. On Wednesday, it announced it was expanding an executive authority to temporarily shield certain Palestinians in the U.S. from deportation.

But in this case, it was the inside game — including private pleas from senators, legislative horsetrading and the concern over a high-profile failed vote — that moved the president’s hand.

Early conversations between lawmakers and the administration began in December. But they got more serious in January, when Van Hollen and his progressive colleagues huddled with Majority Leader Chuck Schumer, telling him they would insist on a vote to ensure military aid recipients complied with humanitarian laws. Their message was clear: If the bill made it to the floor, the Democrats could block the tens of billions of dollars the president had requested for Israel, Ukraine and Taiwan.

Schumer told several people at the White House, including Sullivan, that they needed to talk with the lawmakers, according to a person familiar with the situation who was granted anonymity to relay private conversations.

Over the course of several phone calls and meetings — Van Hollen’s staff counted up 11 hours of wordsmithing between the senator and NSC — the policy was drafted.

The policy requires that before the U.S. hands over weapons and military assistance to another country, the recipient provides written assurance that it will comply with humanitarian law, as well as facilitate U.S. humanitarian assistance in areas of conflict. It also requires the administration to provide Congress detailed reports on whether these countries are adhering to the requirements. If a country violates its assurances, the president can choose to take action up to suspending further deliveries.

The administration viewed the amendment demand and the public attention on the issue as an opportunity to be more clear and transparent that they hold recipient countries to these standards, according to an administration official granted anonymity to discuss the thinking behind writing the memo.

While the desire to ensure passage of the national security supplemental played a major role in Biden issuing the directive, other lawmakers said that the president’s own frustration with the situation in Gaza factored in, too. Sen. Tim Kaine (D-Va.), who backed the amendment push, said the White House “has not been happy” with the pace of humanitarian aid into the region and that the directive allowed them an opportunity to formalize it.

“I think there was an increasing sense of disquiet within the White House national security team about ‘we’re fully in to help Israel defend itself against Hamas, but this is not just supposed to be a war against Palestinians,’” Kaine said. “The White House, more than the politics, may share the same concern and even frustration and felt like an amendment of this kind would give them a way to address their frustration.”

The policy doesn’t require aid to be shut off if countries don’t comply. Biden will merely have the option to do it — a step short of the mandatory compliance that lawmakers such as Sen. Bernie Sanders (I-Vt.) demanded. Human rights advocates have traditionally pushed for strong enforcement mechanisms that would force the hand of an administration reluctant to take dramatic action.

But Van Hollen, Kaine and others insist that the reporting requirements will make it harder for the executive branch to look away.

Sen. Elizabeth Warren (D-Mass.), a longtime advocate of conditioning aid to Israel, called the reporting requirements a “sea change” in terms of how the government approaches “U.S. military aid and its impact on civilians, both because of how explicit it is in describing what the responsibilities are, and how we actually put metrics in that we can see.”

The policy demands that the administration analyze whether a recipient of U.S. aid has used the weapons in line with best practices to avoid civilian harm. The reporting requirements will be backdated to January 2023, allowing the report to cover the war in Gaza.

“I’ve been urging the president all along to make more and more use of the tools that are already available. And now that we have this national security memorandum, we’ve provided the President with a whole additional toolbox,” Van Hollen said. “It’s a big toolbox. He’s really going to have to use it.”

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