America resides unsteadily today upon a knife’s edge of politics. The elections of 2020, including the January 5 runoffs in Georgia, have not only demonstrated a near-parity in the relative power of the two major parties but also a chasm between them in terms of their respective views on the essence of America and the shape of its future. The country has not experienced a definitional crisis of this intensity and magnitude since the decade preceding the Civil War.

What happened at the Capitol building on Wednesday reflects the horrifying breadth of this chasm and the unfathomable depth of anger, vitriol, and anti-Americanism oozing from elements of the Donald Trump constituency. Yes, Trump fanned the flames and incited the ghastly attack, and for that he will be forever tarred with history’s brush of opprobrium. His presidential identity will begin and end with this travesty. And yet that still leaves the haunting question of how he was able to mobilize such people on the basis of a demonstrable lie. Whatever the answer, it remains inexplicably embedded in the hearts of those who perpetrated the civic savagery.

The immediate question for the country, though, is whether, in the wake of this latest outrage as well as other civic lacerations leading up to it, American politics can somehow reestablish a climate of civility in which issues and controversies can be adjudicated in the traditional way. That question rests most prominently upon the new president, Joe Biden, and his party. But a big responsibility resides also with the new GOP minority. Herewith a look at the challenges facing both parties in the context of the imperative of returning America to a sound basis of political give and take.

The Democrats of course now hold the edge in the political arena, based on their control of the White House and both chambers of Congress. But that edge is extremely thin and fragile. Going into the 2020 elections, Democrats held a 35-seat advantage in the House; afterward their margin was only 11, meaning a loss of just six seats in two years will flip the House to GOP control. That’s not a margin that leaves much room for the kinds of initiatives that will increase the divisiveness currently roiling the nation.

Now in the wake of the Georgia runoffs, Democrats also control the Senate—but even closer to near parity, with only the vote of incoming Vice President Kamala Harris, as Senate president, to tip the scales in cases of a tie vote. That’s a margin of control as thin as a butterfly wing and hardly sufficient for any declaration of a bold mandate on the part of President Biden.

And yet, given the chasm between the two parties in political outlook and national vision, pressures will be immense within the Democratic Party for bold action, particularly from the party’s left but also from more moderate elements. Having exiled Trump, the party will want to obliterate Trumpism.

But that impulse to destroy the detested Trump legacy, if acted upon (as likely), will undermine Democratic standing on the margin. And in today’s politics, everything rests on the margin.

Biden is in a bind. If he seeks to govern strictly with Democratic votes, as Barack Obama did in his first two years as president, he risks losing a scattering of his own more moderate party members in Congress—who, on the margin, will need to factor in voter sentiment back home. On the other hand, if he seeks to govern with a broader coalition that includes a few Republicans siphoned off through a more moderate approach, he risks the ire of his party’s left wing, including the fiery Alexandria Ocasio-Cortez and her Squad.

Presidential success in our democratic politics requires a two-step approach. First, the party and its candidate must take control of the presidency and as much of Congress as possible. Then the president must exercise power in a way that pulls together a governing coalition and moves the country in a direction that inspires popular confidence and assent.

A couple examples illustrate this reality. Richard Nixon, a Republican, was elected in 1968 with just 43 percent of the popular vote, with a solidly Democratic opposition in Congress, and no prospect for ever getting a GOP congressional majority in either house anytime soon. He carefully and successfully invested political capital on small issues with bipartisan prospects, built up his political leverage through increasingly more bold initiatives, and ultimately won reelection in a landslide. Democrat Bill Clinton, also a 43 percent president in 1992, lost control of Congress two years later through political ineptitude but then initiated a carefully crafted mode of governing from the center left, scored a number of notable successes, and won reelection solidly in 1996.

At first glance, Biden would seem to be in a better position than these two past presidents, since he won election by a majority 51.3 percent and has both houses of Congress in harness, however tenuously. But that doesn’t take into account the definitional crisis besetting the country and the gaping chasm between the two parties over how to bridge it. That ongoing crisis is generating ever greater political frustrations and tensions, and those in turn will heighten the challenge facing Biden to find a path to coherent governance.

The Republicans face a far different challenge. They must nurture and preserve significant elements of Trumpism while extricating themselves from Trump himself. The outgoing president is so toxic now that he can never be used as a vehicle for reaching a majority coalition in America. But the man won’t make it easy for Republicans to accomplish this difficult challenge and neither will legions of his most fervent supporters.

In the two-step requirement for political success noted above, Trump accomplished the first-step goal in 2016 largely by forcing onto the nation’s political agenda certain issues and policy prescriptions that had been shunned by the political establishment even though they resonated with millions of Americans. Trump devastated the nation’s elites by galvanizing this body of political sentiment into a tight knot of political support from people who had felt marginalized and abused by the system.

But in taking on the second-step challenge–creating a governing coalition and amassing majority support–Trump failed miserably. Having created a base of political allegiance so solid that it couldn’t be penetrated by all the elite institutions of America, he proved himself incapable of building upon that base. That would have required that he operate on the margin, employing convincing and soothing language in talking to people who could be persuaded and bringing them along. It wasn’t difficult to see, even early in his tenure, that he lacked this coalition-building capacity. That’s reflected in a piece that ran in The American Conservative magazine in January/February 2018 entitled: “Trump’s Leadership Void: He’s sputtering in his effort to build a governing coalition.” (Full disclosure: I wrote it.)

Then Trump, having failed to win reelection because of his own political limitations, single-handedly destroyed his party’s dominance of the U.S. Senate by driving a wedge through the GOP with his insistence that evil forces had stolen what should have been his reelection triumph. The Georgia runoff outcome was a direct result of this political malfeasance, but that now pales in comparison to the dastardly attack on the Capitol.

The Trump legacy resides solely in the issues and political thinking that he brought forward during the 2016 campaign. These include the following:

• that the country’s porous-border policies of recent decades, involving both legal and illegal entry, have brought us to a point where challenges of assimilation are most important today in the immigration debate;
• that America’s commitment to free trade has made the country a sucker for abusive commercial practices of our trading partners, particularly China;
• that the hollowing out of the country’s industrial base was a travesty of harmful policymaking that needs to be reversed wherever possible;
• that America’s post-Cold War foreign policy, based on neocon bellicosity and promiscuous military interventionism advocated by Wilsonian liberals, has undermined America’s standing in the world and our ability to leverage our declining power to influence global events;
• that endless U.S. wars in the Middle East and the intensity of our belligerence toward Russia have diminished our ability to deal with our greatest geopolitical challenge, the Chinese resurgence in Asia;
• that the persistent attack on American nationalism by liberal globalists and the ongoing assault on the Western heritage enervates the country by driving wedges through it.

The Democratic Party coming into power now despises nearly all of this and will try to smash it in coming months and years in favor of initiatives designed to bolster federal governmental power and the influence of the country’s elite institutions in the name of humanitarianism. The question facing Republicans is whether they can resist this assault effectively without distancing themselves from the man who put them in their current situation through his own toxicity.

The answer is no, they can’t. In order to stay in the game they must do what Trump couldn’t–namely, fashion a political dialectic and a mode of expression that keeps the Trump coalition intact while ousting the Trumpian fringe and luring to the fold those more centrist folks who are uncomfortable with the current Democratic direction but have been repelled by Trump. Crafting such a dialectic won’t be easy for a party in chaos, as the GOP likely will be in the midst of its current despond. And luring those centrist folks won’t be possible so long as the ghost of Trump hovers over the party.

Robert W. Merry, veteran Washington journalist and publishing executive, is the author of five books on American history, including Where They Stand: The American Presidents in the Eyes of Voters and Historians (Simon & Schuster).