George W. Bush campaigned as a uniter, not a divider, then presided for eight polarizing years, provoking protests like the one against the Iraq War on February 15, 2003, that sent hundreds of thousands of Americans into the streets of major cities. Those protests stopped neither the Iraq War nor the reelection of the president.

Months after Barack Obama was sworn in, on April 15, 2009, protesters associated with the Tea Party held rallies in 350 cities, attracting more than 300,000 Americans. They were angry about the financial crisis, the Bush administration’s response to it, and the progressive agenda of the polarizing new president and Congress. The following year, 84 Republican freshmen joined the House during the 2010 midterms. By 2012, the Tea Party had fueled victories for politicians including Rand Paul, Mike Lee, Marco Rubio, Ted Cruz, Scott Brown, and Nikki Haley. President Obama’s ability to advance a domestic agenda was all but finished, though he retained enough popularity to be reelected easily in the 2012 campaign.

President Donald Trump was inaugurated on Friday. On Saturday, perhaps 3 million Americans turned out for street protests, united mostly by opposition to him.

That is unprecedented.

The crowd estimate is drawn from the work of Erica Chenoweth at the University of Denver and Jeremy Pressman at the University of Connecticut, who tracked down figures from newspapers and other sources around the United States, put them in a spread sheet, cross-checked multiple sources when available, and linked to them all. Adding up their “low” estimates suggests 3.33 million protesters took to the streets. Add up their high estimates and you arrive at a total of 4.63 million protesters. Knock one million people off the low estimate just for kicks and you’ve still got one of the most massive single-day protests in American history. And they’re still adding data from smaller towns that were late to report turnout.

Perhaps the massive turnout isn’t a surprise. Trump lost the popular vote by 2.9 million, even running against a widely disliked Democratic nominee with terrible approval ratings. He enters office intensely hated and with a historically low favorability rating. Many conservative Republicans would prefer that Mike Pence take over if they had their druthers. At the same time, voters gave the GOP House and Senate majorities—so although Sunday’s protests were much bigger a day into the Trump administration than the very biggest day of Tea Party protests, it is too early to discern if they portend a wave of 2018 congressional victories for the Democrats, who are perhaps more divided than Tea Party Republicans ever seemed.

The political future depends on where Trump opponents focus their energy and whether they are adept at expanding their coalition. As Yuval Levin, a conservative who opposed Trump’s rise, put it in one of the articles that Trump and opponents of the president would do well to reflect on, Trump and many of his sharpest detractors share a self-defeating instinct about how to approach the broader public:

Both wish to understand themselves as intensely popular, but both are in fact distinguished by a marked lack of popularity. Trump enters office as the least popular new president since the invention of polling. Yet he insists, and maybe he believes, that he has ridden into Washington on the back of a mass movement the likes of which America has never seen.

The activist Left enters this era having managed to lose a national election to Donald Trump. Yet it behaves as though it takes itself to be the obviously rightful voice of both reason and the masses. Both seem persuaded that they would be even more popular if only they were more like what they already are. They would both be wiser to consider how to broaden their appeal, rather than doubling down on what has limited that appeal and searching for ways to flaunt its reach. Yet both have acted in these opening days of the Trump era in ways likely to intensify the allegiance of those who are already committed and to diminish the chances of drawing more supporters.

Of course, the activist left could and did win a victory Saturday merely by offering visible proof, by way of massive crowd photos in multiple cities, that the vision Trump set forth in his inaugural address is untenable nonsense. “We must speak our minds openly, debate our disagreements honestly, but always pursue solidarity,” Trump declared. “When America is united, America is totally unstoppable.”

But Trump is unusually divisive. The way he has treated women over the course of his life, his ugly campaign attacks on ethnic groups and widely liked individuals, and the appointments he made to key positions guaranteed he will never unite America, even in the impartial way achieved by the most successful presidents. Anyway, no president gets “solidarity” from a free polity of 300 million. You’d think a man who spent much of the last 8 years inquiring after the birth certificate of the last president would understand the inevitability of disunity.

To his credit, Trump is acknowledging that the opposition exists:

Can anyone still believe he’ll unite us after 3 million plus took to the streets on day one of his presidency? Trump is on course to be the biggest divider of them all. Massive protests occurred in Washington, New York, and L.A. But that was just the beginning.

“Tens of thousands of Texans took part in women's marches across the state on Saturday, flooding the streets around the state Capitol in Austin, striding through downtown Dallas and congregating at Houston City Hall,” The Texas Tribune reported.

The Arizona Republic declared that “at least 36,000 people turned out in downtown Phoenix, Tucson and Flagstaff on Saturday to march in solidarity with the Women’s March on Washington,” with other marches in “Prescott, Sedona, Jerome, Gold Canyon, Green Valley, Bisbee and Ajo.” 1,200 marched on Pocatello, Idaho.

Thousands came out for what the local newspaper called one of the largest marches in the history of Colorado Springs, Colorado. A thousand more turned out in Steamboat Springs. 20,000 marched in St. Petersburg, Florida, according to the Tampa Bay Tribune. Police in Atlanta estimated a crowd of 60,000. At a protest in Des Moines, Iowa, “Initial reports estimated there were between 5,000 and 10,000 protestors in attendance, but an updated count estimated 26,000 gathered.”

Up north, “Snow, frigid temperatures and harrowing driving conditions weren't enough to keep thousands of Alaskans from Women's March events across the state.Organizers reported hundreds of people in cities like Palmer, Homer and Juneau. Even remote communities like Adak, located in the Aleutian Islands, reported 10 people in attendance. 38 marched in Unalakleet, a village of 700 people. Anchorage and Fairbanks both estimated march attendance in the thousands.”

The full list of U.S. cities with protests runs past 500.

“For Trump, anything that has to do with wealth, ratings, book sales, crowd size, or poll numbers involves his honor and his sense of self,” Rich Lowry observes. “Plus, he has lived and thrived for decades in the tabloid capital of the world, in part, by exaggerating all these kind of numbers, so it’s become second nature.” How does a character like that respond to millions of people marching against him in the streets, a display unlike anything that he has witnessed since, what, Vietnam?

It is too early to say that Trump cannot salvage greater popularity than he has now, but it will require a sort of conciliation that he has yet to show in political life.

How the right will react is unclear, too.

On Inauguration Day, many conservatives, including Trump skeptics, found themselves looking askance at anti-Trump protests, citing violence and vandalism by a small number of anti-Trump extremists. Those actions are, indeed, deserving of censure. The fact that something like 3 million people gathered en masse in cities across America with almost no problems the following day shows rather decisively that the mainstream of anti-Trump street protesters are peaceful. Imagine a city of 3 million going a whole day without an assault or a shooting. An estimated 500,000 women marched on Washington D.C. without a single arrest.

Other conservatives had substantive objections, like the fraught relationship between Women’s March organizers and pro-lifers. People on both sides of the abortion question can at least agree that it is suboptimal to have a president who bragged about grabbing women “by the pussy” without permission, told a radio shock jock on air that he could call his daughter, Ivanka, “a piece of ass,” and stands accused of sexual assault by multiple women, four of whom marched on Saturday (even if the endurance of abortion as a fissure is inevitable and understandable).

Still other conservatives objected to anti-Trump protests for what might be called aesthetic reasons, like the many signs referencing the female anatomy. Conservative eye-rolling at leftist protest-aesthetic is nothing new, and when the main threat to conservative priorities came from the left it might have made sense. Today, however, a Republican president with zero allegiance to the conservative movement threatens a number of its priorities. And with neither the House nor the Senate held by Democrats, the threat posed by leftist radicals approaches zero.

If one believes, as National Review editorialized, that Trump is “a philosophically unmoored political opportunist who would trash the broad conservative ideological consensus within the GOP in favor of a free-floating populism with strong-man overtones,” and that “Trump knows approximately as much about national security as he does about the nuclear triad—which is to say, almost nothing,” a temporary, narrow anti-Trump alliance with the most powerful forces working against him makes sense, especially when even impeachment would give you President Mike Pence.

National Review added:

If Trump were to become the president... what would that say about conservatives? The movement that ground down the Soviet Union and took the shine, at least temporarily, off socialism would have fallen in behind a huckster.

Indeed, should any conservative fall in behind the most powerful huckster on earth out of visceral distaste for the powerless fringe at protest marches, it will say he or she is being shortsighted and foolish. As the magazine put it, “Trump is a menace to American conservatism who would take the work of generations and trample it underfoot on behalf of a populism as heedless and crude as the Donald himself.”

Meanwhile, online, another mass protest has unfolded more quietly. Trump’s Republican primary opponents were the first to demand that he release his tax returns. Debate moderators, newspaper editorial boards, and Mitt Romney all exerted pressure of their own. On January 11, when Trump was asked by a reporter about his tax returns, he scolded, “You know, the only one that cares about my tax returns are the reporters, okay? They’re the only ones.” Wrong again.

At WhiteHouse.gov, where the Obama administration responded to anything that attracted at least 100,000 signatures, 248,853 people have signed a petition demanding the full release of Trump’s tax returns. Meanwhile, “a team of prominent constitutional scholars, Supreme Court litigators and former White House ethics lawyers intends to file a lawsuit Monday morning alleging that Trump is violating the Constitution by allowing his hotels and other business operations to accept payments from foreign governments,” the New York Times reports. “In the new case, the lawyers argue that a provision in the Constitution known as the Emoluments Clause bans payments from foreign powers like the ones to Mr. Trump’s companies.”

Of course, there is good news for Trump and partisan Republicans. He is president, the GOP controls the executive and legislative branches, judicial nominations are inevitable, and the ability to pass many agenda items is imminent. That millions gathered in the street before Trump has signed anything major into law suggests more huge, ratings-grabbing shows of opposition are likely if, say, masses of Americans lose health care, or there’s a significant push to deport illegal immigrants already living in the U.S. Does that affect the parts of the Trump agenda that the president pursues, or influence the course that Congress takes? Running up the deficit with infrastructure projects that line the pockets of construction industry cronies would presumably result in fewer street protests.

If I were among the activists who planned Saturday’s march I’d consider it a huge success. Like any gathering of perhaps 3 million people, the Women’s March had elements to annoy almost anyone, but for those concerned about Trump’s agenda, or the willingness of Congress to check any abuses he attempts, the Saturday protest was a show of numbers that those in power could not dismiss or ignore.

Whether it can be sustained is another question––one that depends in part on whether the people who constitute the median protester get put off by the least functional peculiarities of leftist activist subculture or stick around to improve it with their input. The Tea Party had a lot more political success than Occupy Wall Street and the anti-war protesters that neither stopped the Iraq invasion nor defeated Bush. Perhaps the right’s brand of results-focused, flag-waving  respectability politics offers some lessons that are compatible with the left’s goals and commitments.

If huge protests continue, it will be fascinating to see how a president who responds so obsessively to popularity and ratings will react. Betraying conservatives and changing course bigly with his agenda? Risking crackdowns on protesters? Attempting to distract Americans with a war? Kicking Mike Pence off the ticket and running for reelection with Ivanka? At this point nothing would surprise me.


Thoughts on any aspect of this article are encouraged—email conor@theatlantic.com