No other issue has roused GOP senators’ wrath at President Trump the way his whitewashing of the murder of Washington Post columnist Jamal Khashoggi has.

The venting over Trump’s refusal to cast blame on Saudi Crown Prince Mohammed bin Salman – who the CIA believes ordered the killing at the Saudi Consulate in Istanbul – is not just coming from retiring GOP moderates like Sen. Bob Corker.

Even Sen. Lindsey Graham, who morphed into a Trump sycophant even before the death of his sidekick John McCain, scornfully dismisses White House insistence that there’s no smoking gun that links the prince to the murder. “There’s a smoking saw” Graham insisted, referring to the fact that the hit team traveled from Riyadh to Istanbul with a bone saw to dismember the body after the slaughter.

Alabama Sen. Richard Shelby (R., Ala.) insisted “all evidence … leads back to the crown prince.” Other GOP senators were so aggrieved they joined a 63-37 Senate vote to start debate on limiting presidential war powers to aid the Saudi-led war in Yemen.

So why has the assassination of a Saudi journalist, albeit a U.S. resident writing for a top U.S. newspaper, stiffened the backbones of so many GOP senators who’ve remained mute over previous White House foreign-policy debacles?

Here are four reasons why the Khashoggi affair resonates far beyond the brutal murder of one man.

1. Trump’s cavalier treatment of other branches of government finally boomeranged. GOP senators were furious that Trump was treating them like fools – given the clear evidence from CIA intercepts that the crown prince directed the Khashoggi hit job. Graham and others were incensed at apparent White House pressure on CIA Director Gina Haspel not to testify before the full Senate body. After she finally appeared at a closed-door Senate briefing, Graham snapped that those who denied the crown prince’s involvement “have to be willfully blind.”

2. Many GOP senators seem to have finally recognized that Trump has hitched his Mideast policy to a reckless prince who has failed to deliver. MBS, as the prince is known, has dragged America into helping him crush a tribal revolt in Yemen that was supposed to contain Iran. Instead, the endless air war has pushed Yemen’s Houthi rebels closer to Tehran and created a staggering humanitarian catastrophe.

Meantime, MBS has split the alliance of Gulf states – a supposed bulwark against Tehran — by blockading Qatar. He rashly kidnapped the Lebanese prime minister in a failed effort to curb Hezbollah. Despite some security cooperation with Israel against their common Iranian enemy, MBS hasn’t delivered on Trump hopes that he would godfather a Mideast peace plan.

Add to that, the prince’s unprecedented crackdowns and jailing of peaceful and moderate Saudi opposition figures, including women activists who led the campaign for women’s right to drive. So much for MBS as a modernizer.

“There was an accumulation [of MBS blunders] building up,” says the Brookings Institution’s Bruce Riedel, author of Kings and Presidents: Saudi Arabia and the United States Since FDR. ”Then the Khashoggi factor burst on the scene.

“The CIA told the White House it was a mistake to put all eggs on the MBS basket.”

Trump, of course, didn’t listen.

MBS is a “wrecking ball to the region, jeopardizing our national security interests on multiple fronts,” says Graham.

3. Yet Trump is treating Saudi Arabia as if it is the senior partner in this relationship and the U.S. is the supplicant. This also angers senators.

Saudi oil production still matters globally, but America’s soaring energy production has changed that balance. And, despite MBS’s ostentatious high five with Vladimir Putin at the recent G-20 summit, the Saudi military, and Saudi security, still depends on U.S. weaponry and training.

The alliance with the country of Saudi Arabia still matters, but that doesn’t preclude Trump’s pushing back against the dangerous behavior of an erratic crown prince.

4. Given all of the above, Trump’s steadfast defense of MBS seeds speculation about his true motivation. Is it his fascination with autocrats and the tribal pomp with which he was treated when visiting Saudi Arabia? Is it son-in-law Jared Kushner’s tight relationship with MBS, which was supposed to guarantee an Israeli-Palestinian peace plan, but hasn’t?

Trump, in his typical transactional fashion, keeps citing the supposed $110 billion in arms deals he concluded with the kingdom. But this is fake news. These are letters of intent, not contracts, and most of the proposals began in the Obama administration. In other words, nothing new and nothing yet concrete.

Another explanation: personal gain. Saudi-funded lobbyists paid for hundreds of rooms at Trump’s hotel after the 2016 election, according to the Washington Post, amounting to $270,000. But is that sum enough to buy Trump?

Whatever the reason, the Khashoggi affair is another instance of Trump’s misjudging a despot. And misjudging how long most GOP senators would act as lapdogs. Expect more pressure on the White House to end support for the Yemen war.

Trump’s devotion to a reckless prince has opened the door for more overt GOP skepticism about a reckless president whose judgment is also seriously flawed.