Amid the confusing details of the deal struck between the United States and Iran this week, one thing was clear: US and Israeli relations have hit a low point.A few months ago the US vice-president was not on board with Donald Trump's operation in Iran, fearing America would again be plunged into a forever war.But as he has tended to do, JD Vance has moved through consternation with the war and is now very publicly supporting the president's vision while making sure his own loyalty is on display too.But this time Vance's grand gesture strikes at the heart of one of the most significant alliances in Western geopolitics.Standing at a White House podium, using language that could not be misinterpreted, the vice-president hit back at Israeli critics of the US-Iran deal to end the war, saying the country should be grateful for the support of the US."Donald J Trump is the only head of state in the entire world who is sympathetic to the nation of Israel at this moment in time," Vance said on Thursday, local time."If I were in the cabinet of the Israeli government, I might not be attacking the only powerful ally that I have anywhere left in the entire world."Over the last three months, two thirds of the defensive weapons that have protected your homeland have been built by American hands and paid for by American tax dollars."The problem for Israel is not Donald J Trump, and anybody in Israel who thinks their biggest problem is the president of the United States needs to wake up and smell the reality of the situation that country is in."It's the strongest message the US has sent to Israel in a public forum for a very long time, if ever.JD Vance met Benjamin Netanyahu in Israel during negotiations over the Gaza ceasefire. (Reuters : Nathan Howard)Analysts believe the remarks reveal the deteriorating relationship between the US and Israel and plunge it further into hostility."They're unprecedented," United States Studies Centre senior fellow Bruce Wolpe said."There have been times when American officials have been very angry with Israel because of the lack of progress on peace."He recalled a moment in 1990 when then-secretary of state James Baker called Israel obstructionist over delays to the Middle East peace process that was underway at the time.Directing his comments towards Israel, Baker said, "When you're serious about peace, call us" and gave out then-president George H W Bush's White House phone number."I can't, since those James Baker [comments], think of any more dangerous moment of hostility between Washington and Jerusalem," Wolpe said."In the immediate wake of where this war has been, it is a stunning development."Jennifer Gavito, a former US deputy assistant secretary of state under Joe Biden and a senior advisor at the Cohen Group, also told the ABC Vance's comments were "unprecedented".She said it should have been predictable that at some point, US and Israeli interests "were going to diverge"."There has been frustration in recent years, including … over the way Israel conducts these operations, first in Gaza but also in Lebanon and the West Bank, whereby civilians are often in the line of fire," Ms Gavito said."Frustration over that is not new, but this scathing public critique is quite unusual, especially for a party that has aligned itself so closely with Prime Minister Netanyahu."Vance becomes face of the dealVance was responding to an Axios report that said Israel was furious, behind the scenes, over the US-Iran memorandum of understanding to end the war.Israeli Prime Minister Benjamin Netanyahu has been silent since the signing, but far-right members of his cabinet have not and pro-Netanyahu media outlets have started to attack Trump too.One prime-time host called Vance a "scumbag".Despite the frankness of his comments, Vance did attempt to separate Netanyahu from the far-right factions making a lot of noise in Israel.Vance has been on a media circuit lately, becoming the public face of the Iran deal.Vance was in Islamabad during peace talks and sat waiting for word his Iranian counterparts would show before he could depart Washington on Air Force Two.He has been interviewed on network television in the US, sat down with podcasters and with the New York Times for an interview in which he had more plain words for Israeli critics of the memorandum of understanding.Trump quipped yesterday that if the deal went well, he would take credit, but if it didn't JD Vance would become his fall guy.It's a typical Trump line and one that Vance hopes is a joke, but knows is not.It is unusual for Trump to permit anyone else to really own a moment, especially one that might involve ending a war, so that tells us there is real political risk in this equation.But it appears Vance has run the numbers.Vance may have political coverAmerican voters are split on their support for Israel and the Republican Party is split on its support for the deal.Some polls put Trump's approval rating at the lowest it's been since he returned to office. The midterm elections are around the corner and Vance has his eyes on 2028.There are a few sums to do, but Wolpe says it is no longer political self-destruction to be publicly critical of Israel, even for a Republican."Republicans are heavily skewed in favour of Israel, but Republicans alone cannot win the election. The big swing is independent voters," he said.Right now, is appears Vance is getting pressure from two wings of the party, while pledging his allegiance to its leader."One, the ultra-MAGA wing led by Tucker Carlson, who believes that this war was completely unjustified and really hurts America's role in the world, [and] what America wants to do at home," Wolpe said.JD Vance has slammed Israeli critics of the Iran deal, saying "Trump is your only ally". (Reuters : Nathan Howard)"And secondly, if there's any political party strongly aligned with Israel, it's the Republican Party, and a lot of Republicans — I think starting with [Republican senator] Lindsey Graham — are concerned that this deal really constrains Israel and its security and is the wrong thing to do."I think Vance is torn between both camps, but it seems clear he is out there now saying the president did this agreement with Iran, give it a chance." Recent weeks have shown Trump is willing to admonish Netanyahu, in particular over Israel's actions in Lebanon.This week Trump said Israel would not exist if it weren't for him, and earlier this month he even admitted to a heated phone call in which he reportedly shouted at Netanyahu and called him "f***ing crazy".In a recent Truth Social post, Trump included the line: "We expect a complete ceasefire on all fronts, including Lebanon, Hezbollah, and Israel."Operation Epic Fury started with Trump and Netanyahu shoulder to shoulder, with the vice-president taking a more muted role.Now, with a deal signed, it is Vance who has come to the fore and he's reminding Israel who is really closer to the Oval Office.The tension between Trump and Netanyahu might be playing out behind closed doors, but Vance, as the salesman of this deal and loyal protector of his president, has cracked them open and revealed how the Trump administration really feels.