(CNN) When the walls were closing on Richard Nixon during his final months in office, the White House and its allies clung to an argument that tearing down the president, a charge they leveled frequently against the press and his congressional inquisitors, was indistinguishable from an attack on the institution he inhabited.

By August 1974, though, Nixon was gone and for the first time in the nuclear age, the parameters of presidential power came under renewed scrutiny.

The War Powers Act, passed over a zombie Nixon's veto in late 1973, and budget reform , which increased legislators' say in federal spending, followed a month before his resignation. A parade of "good government" laws , along with the Church Committee's final report , issued in 1976 after a years-long inquiry into abuses by federal agencies, rounded out the decade.

Americans' taste for more modest leadership had its limits, though, especially in the Cold War era. Jimmy Carter's sweaters and town hall meetings soon gave way to Ronald Reagan and a new period of executive expansion, one that carried on unbroken through five administrations, Republican and Democratic, and into President Donald Trump's chaotic first year in office.

Stress-testing the system, early and often

During his brief time in Washington, Trump has casually trashed the stage-managed status quo refined over decades by his predecessors, openly endorsing his wide authority and, just 10 days after his inauguration, flirting -- for the first time -- with a constitutional crisis by firing the acting attorney general after she refused to defend his travel ban in court.

But early suggestions that Trump's publicly stated disdain for the rule of law, as seen in his attacks on federal judges , and erratic behavior in dealing with nuclear-armed North Korea might compel Congress to consider new restraints on his office have mostly dried up -- even as open bipartisan concern over the breadth of presidential power has bubbled up for the first time in a generation.

In November, Republican Sen. Bob Corker held a hearing to examine, as he put it, "the authority and process for using US nuclear weapons." A pair of bipartisan bills crafted to make it more difficult, or impossible, for Trump to fire special counsel Robert Mueller made the rounds on Capitol Hill in 2017. Meanwhile, conversation about the 25th Amendment , an arcane and untested process for removing a president "unable to discharge the powers and duties of his office," is resurfacing, if only as the stuff of liberal pipe dreams.

The last best chance

The unwillingness of GOP lawmakers to imperil the promise of Trump's ready signature on bills like their 2017 tax cuts goes only part of the way in explaining the current gridlock. Historians point to the ultimately failed or abandoned reforms of the mid- to late 1970s, capped off by the onset of the Reagan era, as a touchstone moment in the rise of the modern "imperial presidency."

"People were lusting for leadership and Reagan projected this viceroy-like, imperial air about him," said Rick Perlstein, chronicler of the postwar conservative movement and author of "Nixonland" and "The Invisible Bridge." "Leadership was the big of word of 1979 and a huge part of the presidential election in 1980. And with (Ted) Kennedy challenging Carter, one of the the big things was the return of the Kennedy grandeur, like we saw in the 'Jackie O' movie. On both the Democratic and Republican side, this idea that the presidency had to become this seat of empire" had come roaring back.

President Ronald Reagan delivering his inaugural address on the west front of the US Capitol, January 20, 1981

Decades on, Trump embraced the expansive authority set before him with unblushing ardor. Where other administrations had at times feigned deference, the new President surged forward headlong , issuing the travel ban, via executive order, a week after taking office.

The tumult of the year that followed, despite the increasingly vocal anxieties of unsettled voters, did little to grow a real appetite among lawmakers for rethinking or shrinking executive power. The reaction, should it come, is more likely to show itself in the rhetoric that colors the next presidential cycle.

"It's very easy to see a 2020 Democratic nominee -- and if Trump goes away, a 2020 Republican nominee too -- campaigning implicitly or explicitly on a platform of 'restoring the presidency,' " Perlstein said, recalling George W. Bush's promise to return "honor and dignity to the White House" two decades earlier, as he ran to replace the scandal-ridden (if popular) Bill Clinton.

But the swamp is as yet unswayed.

"There's not a discourse that's present among opinion-holding elites that even invites" discussion of anything more than surface-level reform, Perlstein said.

Turning outrage into action

Julian Zelizer, a history and public affairs professor at Princeton University, was similarly skeptical that Trump's constant stress-testing of the checks on his power would inspire a serious effort to fortify them -- even with critics and political opponents baying for congressional action.

"Outrage is different than a backlash," Zelizer said. "Meaning: It will really depend on how people vote, what kind of legislators they vote for, what signal they send to the President and Congress in the polls. So we're not quite in the '70s yet. But we're in a moment when we're seeing just how powerful the president can be."

The midterm elections, he added, present the best opportunity, and a slim one at that, for voters to corner lawmakers into considering some manner of material pushback. Even then, there will likely need to be more -- more open corruption, a damning report from Mueller and the prospect of a complete wipeout in the 2020 elections -- to create even the narrowest opening.

"If (the Republicans) really feel that this presidency and this use of presidential power is devastating, and Democrats regain control of Congress, you could imagine that 2019, 2020 becomes a window for reform," Zelizer said. "Because if, in turn, Democrats regain control of everything, they're not going to push for any curbs on presidential power. You need divided government."

Benjamin Ginsberg, a professor at Johns Hopkins University, sees a more trying course ahead for would-be reformers. Trump's behavior, he argued, and the pattern of hysteria that typically follows his frequent Twitter outbursts, has actually further walled off the presidency from any sober judgment.

"If the media treats Trump as an aberration, then the public will happily see Trump as an aberration, and we'll go back to being asleep in our evaluations," he said. "If you point out that Trump is a bit extreme, but is in a way not that different than some of the others -- they were crazy in other ways -- then perhaps the public will get wise."

With Trump supporters eager for him to gobble up more power and opponents militant in their opposition to any analysis that might "normalize" his conduct, that kind of nuanced argument -- no matter how heavily promoted -- seems unlikely to take hold. And the challenge, as Ginsberg concedes, runs deeper than how pundits talk about the administration.

"This partisan struggle is so fierce that there is no one who would step above it," he said. "There is no Republican senator who would go straight to the president and say, 'It's time for you to go.' Or if there's one, there aren't two."

Post-9/11 policies empower Trump

The difficulties facing activists who want to limit presidential power — most recently a mix of conservative libertarians (those untouched by Trumpism) and leftists, along with sympathetic lawmakers — are manifold. Executive power grew by leaps and bounds during the Bush administration, usually under the shady auspices of the post-9/11 war on terror. The Obama White House, most notably with its drone program, carried on down a similar path.

Trump is now pursuing his own goals, using many of the tools bequeathed to him by his predecessors, at a time when global illiberalism is on the march.

"These days it seems like many peoples are gravitating to governmental solutions that involve more executive power," said Ruth Ben-Ghiat, a New York University historian who writes about authoritarian regimes. "In Europe the most desired form of populism is authoritarian populism. So Americans are in some ways part of a larger trend."

Whether he's a product of the moment or simply well-matched to it, Trump has made no secret of his affection for dictators and strongmen . His campaign rhetoric suggested he views himself in their image. "I am your voice," Trump told supporters at the 2016 Republican National Convention. And for all that plagued the country, he declared, "I alone can fix it."

The gathering wave of tribalism in American politics, atop which Trump surfs past dangers other presidents might have turned hard to avoid, is only reinforcing his power, the historians agreed, and degrading the apparatus for crafting reform, now or in the future.

"The more polarized the political landscape, the less possibility there is for cross-party dialogue," Ben-Ghiat said, "and initiatives of the type that one needs to safeguard democracy and limit executive overreach."