It is no wonder that Republican leaders in the House do not want to convene a truth and reconciliation commission to scrutinize the Jan. 6 attack on the Capitol. The more attention drawn to the events of that day, the more their party has to lose.Immediately after the riot, support for President Donald Trump fell sharply among Republicans, according to surveys conducted by Kevin Arceneaux of Sciences Po Paris and Rory Truex of Princeton.The drop signaled that Republicans would have to pay a price for the Trump-inspired insurrection, the violent spirit of which was captured vividly by Peter Baker and Sabrina Tavernise of The Times:The pure savagery of the mob that rampaged through the Capitol that day was breathtaking, as cataloged by the injuries inflicted on those who tried to guard the nation’s elected lawmakers. One police officer lost an eye, another the tip of his finger. Still another was shocked so many times with a Taser gun that he had a heart attack. They suffered cracked ribs, two smashed spinal disks and multiple concussions. At least 81 members of the Capitol force and 65 members of the Metropolitan Police Department were injured.Republican revulsion toward the riot was, however, short-lived.Arceneaux and Truex, in their paper “Donald Trump and the Lie,” point out that Republican voter identification with Trump had “rebounded to pre-election levels” by Jan. 13. The authors measured identification with Trump by responses to two questions: “When people criticize Donald Trump, it feels like a personal insult,” and “When people praise Donald Trump, it makes me feel good.”The same pattern emerged in the Republican Party’s favorability ratings, which dropped by 13 points between the beginning and the end of January, but gained 11 points back by April, according to NBC/Wall Street Journal surveys.Mitch McConnell himself was outraged. In a Feb. 13 speech on the Senate floor he said:January 6th was a disgrace. American citizens attacked their own government. They used terrorism to try to stop a specific piece of democratic business they did not like. Fellow Americans beat and bloodied our own police. They stormed the Senate floor. They tried to hunt down the Speaker of the House. They built a gallows and chanted about murdering the vice president.Memorably, McConnell went on:There is no question that President Trump is practically and morally responsible for provoking the events of that day. The people who stormed this building believed they were acting on the wishes and instructions of their president.McConnell’s indignation was also short-lived. Less than two weeks later, on Feb. 25, McConnell told Fox News that if Trump were the nominee in 2024, he would “absolutely” support the former president.Representative Andrew Clyde of Georgia nearly matched McConnell’s turn-on-a-dime. As The Washington Post reported on Tuesday,Clyde last week downplayed the Jan. 6 assault on the Capitol, comparing the mob’s breaching of the building to a “normal tourist visit.” But photos from that day show the congressman, mouth agape, rushing toward the doors to the House gallery and helping barricade them to prevent rioters from entering.McConnell and Clyde’s turnabouts came as no surprise to students of the Senate minority leader or scholars of American politics.Gary Jacobson of the University of California-San Diego wrote in an email that “the public’s reaction to the riot, like everything else these days, is getting assimilated into the existing polarized configuration of political attitudes and opinions.”Jacobson added:Such things as the absurd spectacle (of the vote recount) in Arizona, Trump’s delusory rantings, the antics of the House crackpot caucus, and the downplaying of the riot in the face of what everyone saw on TV, may weigh on the Republican brand, marginally eroding the party’s national stature over time. But never underestimate the power of motivated reasoning, negative partisanship and selective attention to congenial news sources to keep unwelcome realities at bay.Along similar lines, Paul Frymer, a political scientist at Princeton, suggested that voters have developed a form of scandal fatigue:At a certain point, the scandals start to blur together — Democrats have scandals, Republicans have scandals, no one is seemingly above or below such behavior. One of the reason’s President Trump survived all his scandals and shortcomings is because the public had seen so many of these before and has reached the point of a certain amount of immunity to being surprised.While this mass amnesia seem incomprehensible to some, an August 2019 paper, “Tribalism Is Human Nature,” by Cory Jane Clark, executive director the Adversarial Collaboration Research Center at the University of Pennsylvania, and three fellow psychologists, provides fundamental insight into the evanescing impact of Jan. 6 on the electorate and on Republicans in particular:Selective pressures have consistently sculpted human minds to be “tribal,” and group loyalty and concomitant cognitive biases likely exist in all groups. Modern politics is one of the most salient forms of modern coalitional conflict and elicits substantial cognitive biases. Given the common evolutionary history of liberals and conservatives, there is little reason to expect pro-tribe biases to be higher on one side of the political spectrum than the other.The human mind, Clark and her colleagues wrote,was forged by the crucible of coalitional conflict. For many thousands of years, human tribes have competed against each other. Coalitions that were more cooperative and cohesive not only survived but also appropriated land and resources from other coalitions and therefore reproduced more prolifically, thus passing their genes (and their loyalty traits) to later generations. Because coalitional coordination and commitment were crucial to group success, tribes punished and ostracized defectors and rewarded loyal members with status and resources (as they continue to do today).In large-scale contemporary studies, the authors continue,liberals and conservatives showed similar levels of partisan bias, and a number of pro-tribe cognitive tendencies often ascribed to conservatives (e.g., intolerance toward dissimilar others) have been found in similar degrees in liberals. We conclude that tribal bias is a natural and nearly ineradicable feature of human cognition, and that no group — not even one’s own — is immune.Within this framework, there are two crucial reasons that politics is “one of the most fertile grounds for bias,” Clark and her co-authors write:Political contests are highly consequential because they determine how society will allocate coveted resources such as wealth, power, and prestige. Winners gain control of cultural narratives and the mechanisms of government and can use them to benefit their coalition, often at the expense of losers ….We call this the evolutionarily plausible null hypothesis, and recent research has supported it.Clark argues further, in an email, that rising influence of “tribalism” in politics results in part from the growing “clarity and homogeneity of the Democrat and Republican coalitions,” with the result that “people are better able to find their people, sort into their ideological bubbles, find their preferred news sources, identify their preferred political elites and follow them, and signal their political allegiance to fellow group members (and attain friends and status that way).”Sarah Binder, a political scientist at George Washington University, adds some detail:My sense is that the move by Republican office holders to muddy the waters over what happened at the Capitol (and Trump’s role instigating the events) likely contributes to the waning of G.O.P. voters’ concerns. We heard a burst of these efforts to rewrite the history this past week during the House oversight hearing, but keep in mind that those efforts came on the heels of earlier efforts to downplay the violence, whitewash Trump’s role, and to cast doubt on the identities of the insurrectionists. No doubt, House G.O.P. leaders’ stalling of Democrats’ effort to create a “9/11 type” commission to investigate the events of Jan. 6 has also helped to diffuse G.O.P. interest and to keep the issue out of the headlines. No bipartisan inquiry, no media spotlight to keep the issue alive.In this context, Kevin McCarthy’s announcement on May 18 that the House Republican leadership opposes the creation of a Jan. 6 commission is of a piece with the ouster of Liz Cheney from her position as chair of the House Republican Conference, according to Binder.Doug Mills/The New York TimesAt the end of the day, Binder continued,We probably shouldn’t be surprised that public criticism of the Jan. 6 events only briefly looked bipartisan in the wake of the violence. G.O.P. elites’ decision to make loyalty to Trump a party litmus test (e.g., booting Rep. Cheney from her leadership post) demands that Republicans downplay and whitewash Trump’s role, the violence that day, and the identity of those who stormed the Capitol. Very little of American political life can escape being viewed in a partisan lens.Alexander G. Theodoridis of the University of Massachusetts-Amherst wrote in an email that “the half-life of Jan. 6 memory has proven remarkably short given the objectively shocking nature of what took place at the Capitol that day.” This results in part from the fact thatthere is now seemingly no limit to the ability of partisans to see the world through thick, nearly opaque red and blue colored lenses. In this case, that has Republicans latching onto a narrative that downplays the severity of the Capitol insurrection, attributes blame everywhere but where it belongs, and endorses the Big Lie that stoked the pro-Trump mob that day.A UMass April 21-23 national survey asked voters to identify the person or group “you hold most responsible for the violence that occurred at the Capitol building.” 45 percent identified Trump, 6 percent the Republican Party and 11 percent white nationalists. The surprising finding was the percentage that blamed the left, broadly construed: 16 percent for the Democratic Party, 4 percent for Joe Biden and 11 percent for “antifa,” for a total of 31 percent.The refusal of Republicans to explore the takeover of the Capitol reflects a form of biased reasoning that is not limited to the right or the left, but may be more dangerous on the right.Ariel Malka, a professor at Yeshiva University and an author of “Who is open to authoritarian governance within western democracies?” agreed in an email that both liberals and conservatives “engage in biased reasoning on the basis of partisanship,” but, he argued, there is still a fundamental difference between left and right:There is convincing evidence that cultural conservatives are reliably more open to authoritarian and democracy-degrading action than cultural liberals within Western democracies, including the United States. Because the Democratic Party is the party of American cultural liberals, I believe it would be far more difficult for a Democratic politician who favors overtly anti-democratic action, like nullifying elections, to have political success.These differences are “transforming the Republican Party into an anti-democratic institution,” according to Malka:What we are seeing in the Republican Party is that mass partisan opinion is making it politically devastating for Republican elites to try to uphold democracy. I think that an underappreciated factor in this is that the Republican Party is the home of cultural conservatives, and cultural conservatives are disproportionately open to authoritarian governance.In the paper, Malka, Yphtach Lelkes, Bert N. Bakker and Eliyahu Spivack, of the University of Pennsylvania, the University of Amsterdam and Yeshiva University, ask: “What type of Western citizens would be most inclined to support democracy-degrading actions?”Their answer is twofold.First,Westerners with a broad culturally conservative worldview are especially open to authoritarian governance. For what is likely a variety of reasons, a worldview encompassing traditional sexual morality, religiosity, traditional gender roles, and resistance to multicultural diversity is associated with low or flexible commitment to democracy and amenability to authoritarian alternatives.Second,Westerners who hold a protection-based attitude package — combining a conservative cultural orientation with redistributive and interventionist economic views — are often the most open to authoritarian governance. Notably, it was the English-speaking democracies where this combination of attitudes most consistently predicted openness to authoritarian governance.Julie Wronski of the University of Mississippi replied to my inquiry about Jan. 6 suggesting that Democrats appear to have made a strategic decision against pressing the issue too hard:If voters’ concerns over Jan. 6 are fading, it is because political elites and the media are not making this issue salient. I suspect that Democrats have not made the issue salient recently in order to avoid antagonizing Republicans and exacerbating existing divides. Democrats’ focus seems more on collective action goals related to Covid-19 vaccine rollout and economic infrastructure.Democrats, Wronski continued, appear to have takena pass on the identity-driven zero-sum debate regarding the 2020 election since there is no compromise on this issue — you either believe the truth or you believe the big lie. Once you enter the world of pitting people against each other who believe in different realities of win/lose outcomes, it’s going to be nearly impossible to create bipartisan consensus on sweeping legislative initiatives (like HR1 and infrastructure bills).In a twist, Wronski suggests that it may be to Democrats’ advantage to stay out of the Jan. 6 debate in order to let it fester within Republican ranks:Not all Republican identifiers are strong partisans. Some people may align with the party for specific issue, policy reasons. Their identity is not as tied up in partisanship that an electoral loss becomes a loss to self-identity. This means there are intraparty fractures in the Republican Party regarding the big lie.Republican leaners “seem to be moving away from the party when hearing about intraparty conflict regarding the legitimacy of Joe Biden’s win,” Wronski wrote, citing a May 14 paper by Katherine Clayton, a graduate student in political science at Stanford.Clayton finds thatthose who call themselves “not very strong Republicans” or who consider themselves political independents that lean closer to the Republican Party demonstrate less favorable opinions of their party, reduced perceptions that the Democratic Party poses a threat, and even become more favorable toward the Democratic Party, as a result of exposure to information about conflict within their party.Wronski writes thatthe implication of these results would be for the Democratic Party to do nothing with regards to their messaging of January 6 and let the internal Republican conflict work to their benefit. In a two-party system, voters who do not espouse the big lie and are anti-Trump would eventually align with the Democratic Party.Jeff Greenfield, writing in Politico, takes an opposing position in his May 12 article, “A G.O.P. Civil War? Don’t Bet On It”:It’s getting harder to detect any serious division among rank-and-file Republicans. In Congress, and at the grass roots, the dominance of Donald Trump over the party is more or less total.More significant, Greenfield continued,History is littered with times that critics on the left, and in the pundit class, were positive the Republican Party was setting itself up for defeat by embracing its extremes, only to watch the party comfortably surge into power.Despite Trump’s overt attempt to subvert the election, Greenfield observes, anddespite his feeding the flames that nearly led to a physical assault of the vice president and speaker of the House, the Republican Party has, after a few complaints and speed bumps, firmly rallied behind Trump’s argument that he was robbed of a second term.The challenge facing Democrats goes beyond winning office. They confront an adversary willing to lie about past election outcomes, setting the stage for Republican legislatures to overturn future election returns; an opponent willing to nurture an insurrection if the wrong people win; a political party moving steadily from democracy to authoritarianism; a party that despite its liabilities is more likely than not to regain control of the House and possibly even the Senate in the 2022 midterm elections.The advent of Trump Republicans poses an unprecedented strategic quandary for Democrats, a quandary they have not resolved and that may not lend itself to resolution.The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram. More