No president since Ronald Reagan has achieved a more ambitious domestic legislative agenda in his first year than Joe Biden. With a razor-thin congressional majority — far smaller than that of Barack Obama — President Biden has delivered two enormous spending bills, with another, the Build Back Better act, likely on its way. Elements of these bills will have a lasting effect on the economy into the next decade; they also push the country to the left.

Every president since Reagan has tacked to the rightward winds set in motion by the conservative movement. Even Mr. Obama’s stimulus bill and the Affordable Care Act owed as much to conservative nostrums about the market and runaway spending as they did to liberal notions of fairness and equality. Mr. Biden has had to accommodate the demands of Senators Joe Manchin and Kyrsten Sinema, but their intransigence has not had nearly the constraining effect that the voices of austerity and market fetishism had on Bill Clinton or Mr. Obama.

Yet over the past several months, Mr. Biden’s presidency has been dogged by a sense of failure. Critics, friendly and not so friendly, point to what he has not delivered — voting rights, immigration reform, a $15 federal minimum wage, labor law reform and a path to freedom from personal debt and fossil fuels. Democrats fear that Mr. Biden’s plummeting approval ratings and the party’s losses in the November elections indicate that the Republicans will take back Congress in the midterms.

No president, however, achieves his entire agenda. And presidents have suffered first-term losses greater than those currently anticipated for 2022.

The real cause of the unease about Mr. Biden lies elsewhere. There is a sense that however large his spending bills may be, they come nowhere near to solving the problems they are meant to address. There is also a sense that however much in control of the federal government progressives may be, the right is still calling the shots.

The first point is inarguable, especially when it comes to climate change and inequality. The second point is questionable, but it can find confirmation in everything from a conservative Supreme Court supermajority to the right’s ability to unleash one debilitating culture war after another — and in the growing fear that Republicans will ride back into the halls of power and slam the doors of democracy behind them, maybe forever.

There’s a sense of stuckness, in other words, that no amount of social spending or policy innovation can seem to dislodge. The question is: Why?

A prisoner of great expectations

Though it came out in 1993, Stephen Skowronek’s “The Politics Presidents Make” helps us understand how Mr. Biden has become a prisoner of great expectations.

American politics is punctuated by the rise and fall of political orders or regimes. In each regime, one party, whether in power or not, dominates the field. Its ideas and interests define the landscape, forcing the opposition to accept its terms. Dwight Eisenhower may have been a Republican, but he often spoke in the cadences of the New Deal. Mr. Clinton voiced Reaganite hosannas to the market.

Regimes persist across decades. The Jeffersonian regime lasted from 1800 to 1828; the Jacksonian regime, from 1828 to 1860; the Republican regime, from 1860 to 1932; the New Deal order, from 1932 to 1980.

Reagan’s market regime of deference to the white and the wealthy has outlasted two Democratic presidencies and may survive a third. We see its presence in high returns to the rich and low wages for work, continents of the economy cordoned off from democratic control and resegregated neighborhoods and schools. Corporations are viewed, by liberals, as more advanced reformers of structural racism than parties and laws, and tech billionaires are seen as saviors of the planet.

Eventually, however, regimes grow brittle. Their ideology no longer speaks to the questions of the day; important interests lose pride of place; the opposition refuses to accept the leading party and its values.

Every president presides over a regime that is either resilient or vulnerable. That is his situation. When Eisenhower was elected, the New Deal was strong; when Jimmy Carter was elected, it was weak. Every president is affiliated or opposed to the regime. That is his story. James Knox Polk sought to extend the slavocracy, Abraham Lincoln to end it. The situation and the story are the keys to the president’s power — or powerlessness.

When the president is aligned with a strong regime, he has considerable authority, as Lyndon Johnson realized when he expanded the New Deal with the Great Society. When the president is opposed to a strong regime, he has less authority, as Mr. Obama recognized when he tried to get a public option in the Affordable Care Act. When the president is aligned with a weak regime, he has the least authority, as everyone from John Adams to Mr. Carter was forced to confront. When the president is opposed to a weak regime, he has the greatest authority, as Thomas Jefferson, Andrew Jackson, Lincoln, Roosevelt and Reagan discovered. These presidents, whom Mr. Skowronek calls reconstructive, can reorder the political universe.

All presidents are transformative actors. With each speech and every action, they make or unmake the regime. Sometimes, they do both at the same time: Johnson reportedly declared that with the passage of the Civil Rights Act of 1964, the Democrats had lost the South for a generation, thereby setting the stage for the unraveling of the New Deal.

What distinguishes reconstructive presidents from other presidents, even the most transformative like Johnson, is that their words and deeds have a binding effect on their successors from both parties. They create the language that all serious contestants for power must speak. They construct political institutions and social realities that cannot be easily dismantled. They build coalitions that provide lasting support to the regime. Alexander Hamilton thought every president would “reverse and undo what has been done by a predecessor.” Reconstructive presidents do that — in fact, they reverse and undo the work of many predecessors — but they also ensure that their heirs cannot.

Politics is not physics. A president opposed to the established order may seek to topple it, only to discover that it is too resilient or that his troops are too feeble and lacking in fight. Where we are in political time — whether we are in a reconstructive moment, ripe for reordering, or not — cannot be known in advance. The weakness or strength of a regime, and of the opposition to the regime, is revealed in the contest against it.

What is certain is that the president is both creature and creator of the political world around him. Therein lies Mr. Biden’s predicament.

The language of reconstruction

Heading into the 2020 Democratic primaries, many people thought we might be in a reconstructive moment. I was one of them. There was a popular insurgency from the left, heralding the coming of a new New Deal. It culminated in the Nevada caucus, where people of color and young voters — an emergent multiracial working class — put Bernie Sanders over the top, ready to move the political order to the left.

There also were signs that the Reagan regime was vulnerable. Donald Trump’s candidacy in 2016 suggested that conservative orthodoxies of slashing Social Security and Medicare and waging imperial warfare no longer compelled voters. Mr. Trump’s presidency revealed a congressional G.O.P. that could not unite around a program beyond tax cuts and right-wing judges.

As a candidate, Mr. Biden rejected the transformation Mr. Sanders promised and assured wealthy donors that “nothing would fundamentally change” on his watch. Yet there were signs, after he won the nomination and into the early months of his administration, of a new, “transformational” Mr. Biden who wanted to be the next F.D.R. The combination of the Covid economy, with its shocking inequalities and market failures, and a summer of fire and flood seemed to authorize a left-leaning politics of permanent cash supports to workers and families, increased taxes on the rich to fund radical expansions of health care, elder care and child care, and comprehensive investments in green energy and infrastructure, with high-paying union jobs.

Most important, the package cohered. Instead of a laundry list of gripes and grievances, it featured the consistent items of an alternative ideology and ascendant set of social interests. It promised to replace a sclerotic order that threatens to bury us all with a new order of common life. This was that rare moment when the most partisan of claims can sound like a reasonable defense of the whole.

Yet while Mr. Biden has delivered nearly $3 trillion in spending, with another $1.5 trillion to $2 trillion likely to pass, he has not created a new order. In addition to a transformation of the economy, such an order would require a spate of democracy reforms — the elimination of the filibuster and curbing of partisan gerrymandering, the addition of new states to the union, and national protection of voting rights and electoral procedures — as well as labor law reforms, enabling workers to form unions.

What makes such reforms reconstructive rather than a wish list of good works is that they shift the relations of power and interest, making other regime-building projects possible. Today’s progressive agenda is hobbled less by a lack of popular support than by the outsize leverage conservatives possess — in the Senate, which privileges white voters in sparsely populated, often rural states; in the federal structure of our government, which enables states to make it difficult for Black Americans to vote; and in the courts, whose right-wing composition has been shaped by two Republican presidents elected by a minority of the voters. No progressive agenda can be enacted and maintained unless these deformations are addressed.

The only way to overcome anti-democratic forces is by seeding democracy throughout society, empowering workers to take collective action in the workplace and the polity, and by securing democracy at the level of the state. That is what the great emblems of a reconstructive presidency — the 14th Amendment, which granted Black Americans citizenship, or the Wagner Act, which liberated workers from the tyranny of employers — are meant to do. They give popular energy institutional form, turning temporary measures of an insurgent majority into long-term transformations of policy and practice.

It’s not clear that Mr. Biden wants such a reconstruction. And even if he did, it’s not clear that he could deliver it.

What is stopping Biden?

The forces arrayed against a reconstruction are many.

The first is the Republican Party. Here the party has benefited less from the “authoritarian” turn of Mr. Trump than from the fact that the Trump presidency was so constrained. As Mr. Skowronek argues, “Nothing exposes a hollow consensus faster than the exercise of presidential power.” At critical moments, exercising power was precisely what Mr. Trump was not able to do.

Confronting the free fall of the New Deal, Mr. Carter unleashed a stunning strike of neoliberal and neoconservative measures: deregulation of entire industries; appointment of the anti-labor Paul Volcker to the Fed; a military buildup; and renewed confrontation with the Soviet Union. These defied his party’s orthodoxies and unraveled its coalition. Reagan ended the New Deal regime, but Mr. Carter prepared the way.

For all his talk of opposition to the Republican pooh-bahs, Mr. Trump delivered what they wanted most — tax cuts, deregulation and judges — and suffered defeat when he tried to break out of their vise. Republicans repeatedly denied him funds to support his immigration plans. They overrode his veto of their military spending bill, something Congress had not been able to do in the Carter, Reagan, Clinton, George W. Bush and Obama administrations. Mr. Trump’s own administration defied his Russia policy. This combination of weakness and deference to the G.O.P. helped keep the Republicans — and the Reagan regime — together.

The second obstacle is the Democratic Party. There’s a reason party elites, led by Mr. Obama, swiftly closed ranks, when the time came, behind Mr. Biden and against Mr. Sanders. They wanted continuity, not rupture.

Likewise a portion of the base. Many Democrats are older, with long memories and strong fears of what happens when liberals turn left (they lose). Newer recruits, who gave Mr. Biden the edge in some key districts, usually in the suburbs, are what the Princeton historian Matt Karp calls “Halliburton Democrats,” wealthy defectors from the Republican Party.

“A regime is only as vulnerable as the political forces challenging it are robust,” writes Mr. Skowronek. That robustness is yet to be demonstrated. Despite the clarity of the path the Democrats must take if they hope to topple the Reagan order, it’s not clear the party wants to take it.

The third obstacle to a Biden reconstruction is what Mr. Skowronek calls the “institutional thickening” of American politics. Since the founding era, the American political system has acquired a global economy, with the dollar as the world’s currency; a government bureaucracy and imperial military; a dense ecology of media technologies; and armies of party activists. While these forces offer the modern president resources that Jefferson never had, they also empower the modern-day equivalents of Jefferson’s opponents to resist a reconstruction. Should Mr. Biden attempt one, could he master the masters of social media? Mr. Trump tried and was banned from Twitter.

The real institutions that get in the way of Mr. Biden and the Democrats, however, are not these latter-day additions of modernity but the most ancient features of the American state.

The power of Senators Manchin and Sinema is an artifact of the constitutional design of the Senate and the narrowness of the Democratic majority, which itself reflects the fact that the institution was created to defend slave states rather than popular majorities. Their power is augmented by the centuries-old filibuster, which has forced Mr. Biden to jam many programs into one vaguely named reconciliation bill. That prevents him from picking off individual Republicans for pieces of legislation they might support (as he did with the infrastructure bill).

Should the Republicans take the House in 2022, it will probably not be because of Tucker Carlson but because of gerrymandering. Should the Republicans take back the White House in 2024, it will probably be because of some combination of the Electoral College and the control that our federalist system grants to states over their electoral procedures.

A polarized electorate divided into red and blue states is not novel; it was a hallmark of the last Gilded Age, which put the brakes on the possibility of a presidential reconstruction for decades. As the political scientist E.E. Schattschneider argued, the division of the country into the Republican North and Democratic South made the entire polity “extremely conservative because one-party politics tends strongly to vest political power in the hands of people who already have economic power.”