There are at least two different readings on Rudy Giuliani’s remarkable new legal argument that his client, Donald Trump, could literally shoot the director of the F.B.I. and not break the law. Republicans have generally focused on Giuliani’s larger point: that a sitting president cannot be subpoenaed or indicted, “no matter what it is,” because he must be impeached first. “If he shot James Comey, he’d be impeached the next day,” Giuliani told HuffPost on Sunday, describing the predicament as a simple constitutional matter. “Impeach him, and then you can do whatever you want to do to him.” Legal experts mostly disagree with Giuliani’s interpretation of the law, which has never been explicitly tested and is exceedingly unlikely to win over the Supreme Court. Democrats, however, perceive another sort of danger embedded in Giuliani’s assertion. The legislative branch does have the power to impeach, and it’s nice to think that the current Congress would indeed rule against the president if he killed Comey in cold blood. But what about a lesser crime like, say, obstruction of justice? Even with slightly-better-than-even odds that Democrats retake the House, who believes a Republican-controlled Senate would vote to impeach Trump when the new standard for impeachment is murder?

As Republican lawmakers are well aware, Trump, despite the swirl of scandal surrounding his office, is actually extraordinarily popular with their voters. Five hundred days into his term, 87 percent of the party approves of Trump’s performance, according to Gallup, giving Trump the highest same-party favorability rating of any Republican president at the 500-day mark in the past six decades, with the exception of George W. Bush after 9/11. Indeed, the very things that ought to make the president radioactive actually increase his appeal among the G.O.P.: a recent CBS/YouGov poll found that after his handling of the economy and his general policies overall, nearly 8 out of 10 G.O.P. voters in battleground House races said the thing they liked most about Trump is his commitment to “upsetting the ‘elites’ and the establishment,” a broad term for institutions like the media and civil bureaucracy. Trump’s power is evident, too, in the extent to which he has convinced his allies to despise his enemies—according to Pew, the partisan divide is increasing under Trump, with 45 percent of Republican voters convinced that the Democratic Party is a “threat to the nation’s well-being.” (Forty-one percent of Democrats believe the same of Trump’s G.O.P.)

When national polling isn’t limited to party, Trump consistently ranks among the least popular presidents of all time. But as Trump well knows, as long as the Republican Party is with him, he’s insulated from impeachment. And since his earliest days in office, whether on purpose or via pure intuition, he has made efforts to secure his base and protect his presidency. Fox News, for example, “has become a safe space for Trump fans,” a network executive told my colleague Gabriel Sherman. At this point, there’s almost no daylight between the Murdoch-owned station, Trump’s policy operation, and the deranged conspiracy theories he presents as fact; a person who witnessed the scene told Sherman that shortly after the election, Jeanine Pirro, who regularly delivers pro-Trump screeds on-air, declared, “I really want a job in this administration.” (Pirro declined to comment.) According to The New York Times, Pirro was more than happy to parrot Trump’s own talking points back at him, trashing Comey, Robert Mueller, and Jeff Sessions in a November Oval Office meeting. Other talking heads such as Sean Hannity and Joe DiGenova have joined in, the former of whom famously claimed one of Trump’s pet conspiracies would make “Watergate [look like] stealing a Snickers bar from a drugstore” (it turned out to be a dud), and the latter of whom recently called Sessions’s recusal from the Russia probe “an unforced betrayal of the president of the United States.”

Inextricable from the Fox feedback loop is Trump’s Twitter feed, where he test-drives formulaic efforts to discredit his enemies and makes direct appeals to his fans. Together, these entities give Trump an eerie ability to move the goalposts, all the while cajoling his own party into following his lead. By way of example, look no further than Trump’s war with Amazon: driven by his hatred of Jeff Bezos, whom he blames for The Washington Post’s critical coverage of him, the president has gone from threatening the tech giant to reportedly “personally push[ing] U.S. Postmaster General Megan Brennan to double the rate the Postal Service charges Amazon.com.” In any other administration, this would have ramifications. But thanks to the combination of his uniquely effective propaganda machine and a docile Republican electorate, Trump’s open hostility toward the company has gone completely unchecked.

That Congress has followed Trump this far down the rabbit hole suggests that its standard for impeachment may have become insurmountably high—that even if Mueller finds fault in the president or his campaign, those who have the power to hold him accountable may not act. “I could stand in the middle of 5th Avenue and shoot somebody and wouldn’t lose any voters,” then candidate Trump said during a January 2016 campaign rally in Iowa. “It’s, like, incredible.” More than two years later, with his popularity among Republicans all but negating traditional checks and balances, his claim may prove oddly prescient.