Impressionists have second-class-citizen status in comedy. Even Steve Coogan once dismissively compared his and Rob Brydon’s spectacular Michael Caine–off in The Trip to watching a juggler: impressive but meaningless. Yet, maybe precisely because impressions delight so readily and so broadly, requiring a minimum of analysis, they can offer a kind of funhouse mirror for the zeitgeist. After all, one of the pillars of Saturday Night Live’s ever-regenerating bid for relevance has always been its impressions — and the summa of its imitation game, I’d argue, is the president of the United States

Funnily enough, SNL’s ur-POTUS impression wasn’t much of an actual impression. Chevy Chase as Gerald Ford quickly became iconic — the New York Times even published a piece by Chase when Ford died — even though the comedian captured so little of the actual Ford. For me, and I suspect for a lot of people to whom Watergate was just a hefty chunk in an A.P. U.S. history course, the enduring mental image of Ford is a 110 percent committed Chase taking a dive off a toppling Christmas tree. In fact, the real Ford may have been the most athletic man to sit in the Oval Office — he almost played professional football. But Chase harped on his Air Force One stumble so relentlessly that people actually debated whether it cost Ford the ’76 presidential race.

I highly doubt that, but it sounds compelling doesn’t it? What Chase’s impression really did was distill an idea. There was no subtle critique of policies, no parody of personality, no character insight. Instead, Chase’s blundering was an emblem of someone thrust awkwardly into a role he might not quite be ready to play: It’s impression as abstraction or even surrealism. It was Dada Ford. What, if anything, did that say about America? That a country whose ideals had been so badly bruised by Watergate wasn’t ready for trenchant satire yet? That the political conversation was so fully cooked over the mere fact of Ford in the Oval Office — let alone his pardoning Richard Nixon — that all we wanted was pure, Chaplinesque physical comedy? Maybe. But what it immediately meant was that future leaders of the free world would now and forever have to reckon with Saturday Night Live as mocker-in-chief.

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After Chase left and Jimmy Carter was elected president, that duty fell to Dan Aykroyd. His Carter brought the presidential impression back into the world of caricature — though interestingly Aykroyd refused to get rid of his mustache for either his Carter or retrospective Nixon impressions. But now, with the immediate legacy of Watergate growing more distant, we were ready to look our faux-commander-in-chief squarely in the eye and laugh at him. Aykroyd nailed Carter’s earnest Southern lilt, adding a twist of his slickster salesman from the famous Bass-omatic sketch. Aykroyd’s mustache was almost a badge: He formed his Carter so concretely that you were willing to erase it in your mind’s eye. This time, not only was America ready to laugh at Carter’s homespun advice — wear that sweater! — it needed to. (With the passing of time, Aykroyd was also free to take on Nixon and transform the Shakespearean villain into a brooding, megalomaniacal buffoon who called John Belushi’s blushing Henry Kissinger “Jew Boy.”)

Then came Ronald Reagan, ironically the biggest lacuna in SNL’s Hall of Presidents. Initially, it must have been hard to make fun of the sunny optimism, the mood that would become “Morning in America”: The last thing you want to do is mock the football team during homecoming. It didn’t help that SNL was in its nadir Joe Piscopo years after Lorne Michaels’s temporary departure. Who remembers Piscopo’s impression? Only the Internet. It wasn’t until late in the game that SNL’s truly memorable Reagan impression came, with the arrival of Iran Contra and one of the show’s true greats, Phil Hartman. The signature sketch was written by Robert Smigel, and helped along by Jim Downey, George Meyer, and current U.S. senator Al Franken. Their simmering outrage at Reagan’s memory “lapses” gives the writing an effervescent brilliance, perfectly executed by Hartman. By now the bloom was off Reagan’s rose, so the writers took aim at the Great Communicator’s muddled memory by imagining just the opposite: Reagan as the true Nixonian mastermind behind Iran Contra, a man who wears his absent-minded grandfather’s smile as the ultimate camouflage. Hartman dances with astonishing dexterity between the two faces of Reagan; his expressions could always turn on a dime. He gamely jokes that a Girl Scout doing a photo-op should be his ambassador to the recalcitrant Democratic Congress; after she leaves, he springs into action, excoriating aides for not being able to follow his Machiavellian strategy to fund the Contras. Finally, an irritated American public, buoyed by the growing economy of the ’80s and disgusted by yet another high-reaching scandal, was ready for some pointed humor. It was the comic exorcism of the ghost of Nixon from our political psyches, SNL at last relevant again. It’s also still hilarious as hell.

The SNL tradition of must-watch presidential impressions would be secured with Dana Carvey’s infinitely elastic George H.W. Bush. Less accurate than salient, Carvey took Bush Senior’s penchant for dry polit-babble to its naturally absurdist conclusions. The short Carvey looked nothing like the towering Bush, so instead he worked by isolating key phrases from the president’s authoritative double-talk — “wouldn’t be prudent” and “not gonna do it” (later reduced to “na ga da”) — and putting them through the food processor of his hand gestures. It felt less like political commentary than the class clown making fun of teacher for the school talent show: resonant but far from biting. What was notable about Carvey’s impression was its focus on personality. That instinct seems to have informed every SNL impressionist after him. Getting belly laughs out of “no new taxes” is a fool’s errand. Instead, Carvey took a strand in Bush Senior and stretched it out like water taffy. If anything, it endeared Bush to us as a wacky and proudly out-of-touch old man. In fact, it gave him more credit for folksiness than the lofty Connecticut Yankee probably ever intended. And what did it say about that early ’90s, enduring a recession that now looks quaint by comparison? Here’s my guess: that there was an air of bland, reassuring consensus underscored by light dissatisfaction. We didn’t want to rock the boat too much, just giggle at our aging elders — the greatest generation who didn’t quite get it anymore. You could appreciate Bush Senior’s deep understanding of government while still suspecting his hand at the helm shook a little more than was ideal. Carvey’s parody was silly, resonant but gentlemanly; Bush, ever the patrician paterfamilias, could apparently appreciate it with removed benevolence. Suddenly, the president was doing quick cameos on SNL.

Then came Bill Clinton, and nothing would ever be the same. It took a beat before the full depth of the comedic goldmine that was the Clinton presidency become truly apparent. Not surprisingly, Phil Hartman came out swinging with an interpretation steeped in slick Southern charm and baby-kissing: His Clinton jogs into a local McDonald’s, charming wide-eyed “regular” folks while sneaking a bite of everyone’s meal. But after Hartman left, SNL’s longest-running cast member and maestro of impressions, Darrell Hammond, took over at just the perfect moment. Hammond had about as juicy a comedy streak of presidential follies as you could hope for, and he hit it out of the park. Isolating (and combining) Clinton’s “feel your pain” thumb gesture with a naughty lip bite, Hammond played Clinton like an alto sax on Arsenio. He rocketed beyond the cliché of the Southern politician and sculpted a gleefully unapologetic hound dog armed with epic charisma. If anything, his impression captured how Clinton’s personal faults actually worked like a snake charmer’s flute: They only made us love him more. Hammond’s impressions deliciously riffed on that seductive through line over and over, with slight adjustments provoking fresh laughter every time: Hammond’s Clinton was the “Goldberg Variations” of SNL presidents. And as the real Clinton beat back Mount Scandal, Hammond’s impression became less satire than performance art: How far could Hammond go and still retain the fundamental essence of a man who himself pushed all the boundaries? In the end, he was limited only by that constitutional buzzer of term limits.

It seemed like an impossible act to follow: Given the choice, the infinitely gifted Hammond opted to take on Al Gore rather than George W. Bush for the 2000 election season. Initially, Bush felt so paper thin, with that vacant, smarmy grin of his, that you figured Will Ferrell would have to go full-tilt bizarre, à la Janet Reno’s dance party. Dana Carvey was even called back to pass the torch. Of course, Ferrell ended up as SNL’s arguably most popular fake president: No one else got that one-man Broadway show. Ferrell’s Dubya is so entrenched in our hearts, it’s easy to forget he really only had a few seasons with Bush in office before leaving SNL. Will Forte, Chris Parnell, and others would take on the task, but who remembers that? Ferrell’s impression speaks for itself; it’s the quintessence of caricature. He didn’t play the same chord of sarcastic indignation that works so well for Jon Stewart. Instead, Ferrell made Bush into a lovable douche: In the wake of 9/11, Ferrell’s sketch was almost a rally cry in itself. But as the goodwill that Bush’s post-attack leadership earned him was burned away in the fires of Iraq, Ferrell’s impersonation soldiered on. It was both tonic and scourge. All the underlying angst of the Iraq war, America’s ballooning cultural excess, and the foreboding of an inevitable headache to come was sublimated into a Dionysian release of gallows laughter at our nation held hostage by Bush’s buffoonery. Ferrell’s Bush gave us emperor-has-no-clothes moments upon moments until we ultimately realized we were really laughing at ourselves. Ferrell’s final Bush sketch — offering Senator John McCain and Governor Sarah Palin his endorsement in the wake of the 2008 financial crisis — plays like grim catharsis. We knew we had this coming, but Ferrell had kept us laughing all the way to the slaughterhouse.

Obviously, we have to make space for Tina Fey’s Palin, even if she was never technically president. I’m skeptical of Chevy Chase’s impact on Gerald Ford, but I have no doubt about Fey: She burst the bubble that was Sarah Palin. Palin dug her own grave, but Fey’s sketches — underlined by her uncanny resemblance to the Alaska governor — had the sharpest edge of purposeful satire to them. This wasn’t the kind of chummy goofiness that could leave the real Palin and Fey golfing buddies. In fact, when Palin did her requisite (cynical) SNL cameo to prove she could laugh at herself, Fey refused to share the stage, appearing with Lorne Michaels to avoid any hint of endorsement. You might not immediately see it with Fey’s pitch-perfect parody of Palin’s Katie Couric interview. But it’s there. When Fey’s Palin found her contrast with Amy Poehler’s Hillary, the underlying outrage becomes apparent: How could Sarah Palin come closer to the Oval Office than Hillary Clinton? Beneath the surface mockery of faux-folksiness, Fey had an agenda: Get this person off the political stage. And if any comedian has ever had any real impact on politics, it has to be Tina Fey.

Which leads us to the present day and Barack Obama. Initially, the historic nature of his election left Fred Armisen with an impossible task: How do you mock hope? You don’t. Despite meticulously capturing Obama’s mannerisms, Armisen’s impression had no bite, waterlogged by the surfeit of collective goodwill for Obama. Poor Fred: He even suffered a New York Times article calling him out on it. Fortunately, Armisen would find Portlandia and Lorne Michaels would find Jay Pharoah. It helps that by the time Pharoah came around, the idealism of Obama’s initial election gave way to the reality of a presidency. Obama has now suffered more than his share of grief and failures, giving Pharoah actual grist to work with — although he’s avoided the opportunity to take any pointed swipes. As well-honed as Pharaoh’s impression is, it has slowly become more a vehicle for current-event commentary — Nelson Mandela’s funeral, the lack of African American women in SNL’s cast, the silliness of viral marketing strategies — rather than the show itself, like Ferrell’s Bush or Fey’s Palin. Obama plays straight man to the week’s events; and this past season, he’s taken a backseat to Pharaoh’s Kanye. Could it be a sign, a collective willful averting of the eyes from the fact that the Obama presidency could never live up to the hype of the campaign, especially given a historic recession? Or is it just that universal health care is so hard to poke fun at that you need a Breaking Bad cameo? Either way, Obama won’t officially be a lame duck until after this year’s midterms — but on SNL he already is.

But comedywise, that’s exciting. 2015-16 will inevitably bring the return of the Clintons and perhaps Rand Paul. Could this be Taran Killam’s time to shine? Will we get a few more choice moments with Pharaoh’s Obama once he finally checks out? Who knows, but once the campaign season kicks off, Lorne Michaels’s newest bunch of Not Ready for Prime Time Players get ready fast. They have big shoes to fill.

Illustration by Linsey Fields