As Israel's national security advisor and a senior US diplomat signed the 10-year deal there was no sign of the distrust that has soured relations between President Barack Obama and Prime Minister Benjamin Netanyahu.
In recent weeks Washington has toughened its criticism of Israel's accelerated building of settlements on occupied land in East Jerusalem and the West Bank, warning that it could destroy hopes for peace with the Palestinians.
And Israel has made no secret of its fierce opposition to Obama's signature diplomatic initiative, the outreach to Iran which last year led to a deal to restrain Tehran's nuclear program in exchange for sanctions relief.
- Greatest friend -
Beyond that, Netanyahu and Obama have often rubbed each other up the wrong way and, while the Israeli leader has been accused at home of putting the alliance at risk, the president's domestic foes accuse him of snubbing his ally.
But the US-Israeli alliance pre-dates both men and the new 10-year deal will cover the terms of the next president too. The White House insists that the relationship is unbreakable and at the core of US regional strategy.
"For as long as the state of Israel has existed, the United States has been Israel's greatest friend and partner, a fact underscored again today," Obama declared, in a statement released to mark the signing.
But he continued pointedly.
"It is because of this same commitment to Israel and its long-term security that we will also continue to press for a two-state solution to the longstanding Israeli-Palestinian conflict, despite the deeply troubling trends on the ground that undermine this goal," he said.
"As I have emphasized previously, the only way for Israel to endure and thrive as a Jewish and democratic state is through the realization of an independent and viable Palestine."
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The deal covers the period from 2019 to 2028 and will see Israel receive $3.3 billion per year in foreign military financing -- up from $3.1 billion per year currently -- and $500,000 per year in funding for missile defense.
Even before this record package, Israel was already the biggest single recipient of US military aid from the State Department's foreign military financing budget, receiving itself more than half of the funds.
But the warm words at the ceremony and the historic nature of the sum could not fully paper over the tough negotiations that got the parties there -- and Israel did not get everything it wanted.
The deal will cover a decade in which Netanyahu's government fears that its old foe Iran -- released from international sanctions on its nuclear program -- will become even more aggressive in the region.
- Iron Dome -
Israeli reports have suggested that he sought up to $4.5 billion per year to maintain his army's quantitative and qualitative edge over its neighbors, and Netanyahu's friends in Washington were quick to complain.
And the huge headline figure of $38 billion came about by adding much of the funding that the United States already provides to support the "Iron Dome" missile defense system to the broader military financing package.
"We're almost the same as where we are right now," said Jonathan Schanzer, former US counter-terrorism analyst and vice-president of Washington think tank the Foundation for the Defense of Democracies.
And, while Israel will now be able to buy more of the latest F-35 fighter jets and CV-22 Osprey tilt-rotor planes from American firms, it has lost a key source of support for its thriving defense industry.
According to the White House, under the arrangement Israel will lose its right, unique among US allies, to spend 26.3 percent of its US funding with its own arms manufacturers and will instead have to buy American technology.
Nevertheless, the alliance -- "iron-clad" in the words of US National Security Advisor Susan Rice -- remains, despite or perhaps even in part because of Obama's need to prove his feud with Netanyahu has no strategic consequence.
"It's a constant in the Obama administration: personal relations are terrible but everyone agrees the military relationship has never been stronger," Joseph Bahout of the Carnegie Endowment for International Peace told AFP.
"That's the paradox. What we hear from Israeli officials is that they can't stand this administration but they've never been so spoiled, and Obama can insist that no one can accuse him of not loving Israel."