Egypt called for a vote at the UN General Assembly after the US vetoed a resolution put to the Security Council rejecting Washington's decision to recognize Jerusalem and relocate its embassy there. The US cannot veto General Assembly motions, which require a simple majority to be adopted.
"We're watching those votes," Trump said Wednesday.
"Let them vote against us, we'll save a lot. We don't care. But this isn't like it used to be where they could vote against you and then you pay them hundreds of millions of dollars and nobody knows what they're doing."
The fourth biggest recipient of military funding however, is far more sensitive. Egypt received $1.1 billion from the DOD's Foreign Military Financing program and it's Cairo which is leading the push at the UN to condemn Trump's Jerusalem decision.
US funding has made up around 20-25% of Egypt's total military budget in recent years, according to statistics from the International Institute for Strategic Studies. No other country gives a comparable amount in military assistance to Cairo.
Any long term cutting off of aid to Egypt's military -- which has run the country since a coup in 2013 -- is unlikely. US spending in Egypt ramped up after Cairo signed a peace treaty with Israel in 1979, and the country remains vital to US security interests in the wider region.
Overseas development assistance
Military spending may be the biggest cudgel Washington has to bring to bear, but it's also the least likely to be cut.
Overseas development assistance, such as that provided by USAID, is a more likely target for cuts -- though reductions would still have a knock on effect on US businesses and citizens who rely on projects funded by donor programs.
Of the top 10 recipients of USAID money in 2016, many were African nations, including Ethiopia, South Sudan, Kenya, Nigeria and the Democratic Republic of the Congo (DRC). Unlike Middle Eastern nations, which will face strong pressure internally to condemn the US Jerusalem move, these countries are also potentially less invested in supporting the Palestinians.
However, unlike in the Middle East and North Africa, where US assistance, particularly militarily, makes up a large portion of the total, African nations also receive significant funding from other sources.
South Sudan will be more wary of losing US funds, which were more than the next four top donors combined, but Kenya, Nigeria and the DRC all receive significant sums from other sources, particularly the World Bank and the UK.
Nick Bisley, a professor of international relations at Australia's La Trobe University, said any move by the US to cut foreign assistance would be seen as a major opportunity by China.
"If (Washington) were to follow through on this threat, people who had that money withheld can go to Beijing," he said, where China's leaders are very much "in the market for winning friends and influence."
Trump's words on Jerusalem over the years01:54
Breach of diplomatic norms
It's difficult to judge how seriously to take Haley and Trump's threats, and whether they are being followed up with behind-the-scenes diplomatic pressure on certain countries to vote in Washington's favor.
But it remains almost impossible the US could sway enough countries to avoid censure by the General Assembly, where only a simple majority is required. Nor will US pressure necessarily have the effect Washington hopes.
"Personalizing it, making it a vote for or against President Trump, is a bizarrely stupid tactic," said Richard Gowan, a New York based UN expert at the European Council on Foreign Relations.
A senior foreign diplomat, who spoke anonymously to protect relations with the US, told CNN Wednesday "no matter how close we can be to the US, we are keen to keep up our longstanding attachment to UN Security Council resolutions on the Jerusalem status."
"For many members, especially Western ones, their votes reflect positions they've held for 50 years," the diplomat said. "The two-state solution, the status of Jerusalem through negotiation, etc. — they are supposed to abandon 50 years of policy, for what exactly?"
Bisley said Trump and Haley's rhetoric was "pretty crude and unsophisticated" and symptomatic of the administration's lack of a broader view of world affairs and the US role in them.
"They see everything in a short-term, reactive way, and don't see how this has negative repercussions for global influence," he said. "There's a real lack of big picture thinking and sense of the big, interconnected world out there."
The diplomat added any significant US pressure on this issue could leave Washington isolated when it needs UN support on issues like North Korea or Iran.
"Most of the time, the diplomatic community in New York is willing to put up with (Haley's) rhetorical flourishes," said Gowan. "This week is a bit different."
CNN's Nicole Gaouette, Richard Roth and Michelle Kosinski contributed reporting.