As President Biden marked his first 100 days in office with a speech to the nation Wednesday, the scope and implications of his domestic agenda have come sharply into focus. Together they represent the most dramatic shift in federal economic and social welfare policy since Ronald Reagan was elected 40 years ago.

Reagan’s small-government philosophy resulted in a decades-long squeeze on the federal government, especially domestic spending, and on tax policies that mainly benefited the wealthiest Americans.

If Biden ultimately gets his way legislatively, and that is a big question mark, those policies would be replaced with ones that would directly address long-standing economic, racial and gender inequities that have only become more apparent during the coronavirus pandemic.

Biden had to wait nearly 50 years to achieve his dream of becoming president. In office, he is operating as if he has no time to spare. Throughout his first 100 days, and again on Wednesday night, the presentation of his agenda shows he believes there is an urgent need to act and an opportunity to do so, but that he has limited time to get it done.

Biden said that to win the competition for the future, the nation needs “a once-in-generation investment in our families and our children.”

His speech was a reflection of his presidency to date: an appeal for big and bold action described in the most workaday rhetoric and by a leader whose demeanor and temperament are the very opposite of his predecessor, former president Donald Trump.

But given the Democrats’ narrow majorities in Congress and a nation still sharply divided over the president’s performance, Biden’s agenda represents a policy and political gamble of enormous proportions, one that will be adjudicated in both the 2022 midterms and the 2024 presidential election. The politics of redistribution, which are at the heart of what Biden is proposing, could test decades of assumptions that Democrats should be afraid of being tagged as the party of big government.

It is unusual in the modern era for a new president to wait until the 100-day mark to address a joint session of Congress. By now, Biden has had months to shape, offer and begin to move the major elements of his agenda. In that way, Wednesday’s speech was both a summing-up and a call to action.

To date, the politics of the coronavirus pandemic have been central to Biden’s presidency and agenda. Ramping up the pace of vaccinations and moving the country toward a gradual loosening of restrictions, both economic and personal, have been his highest priorities. But as those conditions continue to move closer to pre-pandemic norms, the rest of his agenda will come to the forefront, and with it, a charged debate. Biden’s hope is that the progress on the coronavirus translates into greater public confidence in his leadership in other areas.

If the main outlines of what Biden talked about Wednesday night seem familiar, they are anything but ordinary, beginning with the sheer cost of the three major elements of his spending plans that have already been announced.

Together, the already approved coronavirus relief plan, the infrastructure proposal that was unveiled a few weeks ago and the newly proposed plan to invest in social welfare programs would total roughly $6 trillion, much of it aimed at middle- and working-class families. Biden would pay for much of the infrastructure and family spending with increased taxes on corporations and on the wealthiest Americans.

“My fellow Americans, trickle-down economics has never worked,” Biden said. “It’s time to grow the economy from the bottom and middle out.”

House and Senate Republicans on April 25 rated President Biden's response to the border crisis, foreign policy and tax plans ahead of his formal joint address. (Amber Ferguson/The Washington Post)

Republicans have branded the president’s agenda as radical, and perhaps by the party’s prior standards — by the standards of the Reagan era — that is the case. It does represent a major departure. But it is also true that Trump embraced tax cuts and coronavirus spending that totaled well over $4 trillion — tossing aside long-standing Republican concerns about deficits and government spending — and also called for a massive infrastructure program of his own, though he never really pushed it.

In other words, the landscape began to change before Biden took office. But it is also the case that Biden has resisted advocating things like single-payer health care that could trigger the kind of political backlash the occurred when President Barack Obama successfully passed the Affordable Care Act. And as happy as many liberal Democrats are with the way Biden is governing, he has not fully embraced all that they would like to see done.

In other times, the $6 trillion cost might have produced sticker shock for many Americans, and perhaps that eventually will be the case. But the programmatic details, where the money would go, so far focus mainly on broadly popular programs, from $1,400 checks to individuals and child tax credits in the coronavirus relief plan to things like universal prekindergarten for 3 and 4-year-olds, two years of free tuition at community colleges, access to affordable child care, paid family and medical leave, and home health care for the elderly.

Government spending on social safety-net programs has been reduced compared with previous years. Over the past decade, needs have gone unattended because of the standoff between congressional Republicans and Obama, the sheer obstructionism of the GOP’s right-wing faction in Congress — whose members resisted virtually all spending — and then the angry politics of the Trump years.

The pandemic and the killing of George Floyd helped shine a bright light on the inequalities in the economy and the social structure, highlighting racial gaps in health care; the crushing of service-sector workers and their families as the hospitality, tourism and restaurant industries took major hits; and the departure of many women from the workforce because the absence of child care and the closing of schools fell most heavily on them.

Biden’s agenda represents a significant rebalancing of the nation’s priorities, though the effects will take considerable time to be fully felt. Money in the coronavirus relief package will be disbursed over the next few years. The money in the two packages that are in negotiation on Capitol Hill would be spent over a much longer time frame, but those trillions would have the greatest impact on changing national priorities.

Public opinion is mixed as Biden pushes to enact the rest of the agenda. The relief package is highly popular, while the infrastructure package enjoys less support, though still a slight majority. There is no current polling on the most recent package, the American Families Plan.

Support for bigger government has shifted since the early part of the previous decade and now stands statistically the same as support for smaller government with fewer services. But when people are asked about Biden, 53 percent say they are concerned that he will do too much to increase the size and scope of government compared with 45 percent who say they are not concerned about that, according to the most recent Washington Post-ABC News poll.

What makes Biden’s situation unique from those of past presidents who have pushed for major changes — whether Franklin D. Roosevelt, Lyndon B. Johnson or Reagan — is the difference between sizable real or working political majorities and the thinnest possible majorities upon which Biden’s hopes rest.

Biden is attempting transformative change on a base smaller by far than any of those previous presidents enjoyed, which is what makes the political gamble so big. If he succeeds and the economy roars through 2022 and then the public decides that, rather than concerns about deficits and spending, they prefer a government attending more aggressively to the social inequities, then Biden and the Democrats could prosper. But if things were to go the other way, that could easily put Republicans back in the driver’s seat and allow for the reappearance of Trumpism.

“The Biden administration is making an enormous wager on a certain vision of the future,” said William Galston of the Brookings Institution. “If they turn out to be right, it will not only be transformational but celebrated in history as such. It will have leveraged the thinnest possible political majority into very large accomplishments. But simply to state that thesis is to illustrate just how remarkable it would be if this line of policy and if this political strategy prevails.”

Negotiations lie ahead and Biden has signaled he’s prepared to make some changes. But in broad strokes, he has set his course and it is anything but timid, incremental or risk-free.