Something significant happened last week when Senate Democrats announced a meeting of the minds on the price tag for their go-it-alone infrastructure package. The entire Democratic caucus – from Bernie Sanders on the left to Joe Manchin on the right – agreed in principle to spend $3.5 trillion on a wide range of progressive policies and pay for them by raising taxes on the very rich. Billed as human infrastructure, the bill is really the entire Biden economic and social agenda wrapped tightly into one piece of legislation designed to pass the Senate on a party line vote through the process called reconciliation.

What’s under the $3.5 trillion umbrella? It may be easier to ask what isn’t. Medicare expansion is in the bill. So is universal pre-K and free community college. It has elements of the Green New Deal (while sidestepping that politically explosive term). Even immigration reform is in the package. The strategy is to bundle as much high-impact policy as possible into one bill, give it the benign “infrastructure” label, then get every Democrat behind it and pass it all with one vote.

This strategy, these measures, and the philosophy behind both are unlike anything we’ve seen before. The prevailing assumptions about taxing and spending in force since the Reagan administration made it impossible for Democrats to advance bold social programs or raise taxes to pay for them. The political risk was too great, because the electorate was inclined to punish officials who could be characterized as supporting big government or higher taxes. In the rare moments when they tried, they either suffered policy and electoral defeat (Bill Clinton’s failed effort to reform healthcare and the Democrats’ subsequent loss of Congress) or sustained a loss of public confidence after a protracted and ultimately vain attempt to get bipartisan cover from Republicans (Barack Obama’s successful but tortured effort to reform healthcare, which also led to the Democrats’ loss of Congress).

What changed? Covid-19 and the shock to the system that was the Trump administration have opened up political space that didn’t exist before. We have been gradually moving toward a sea change in attitudes about government as the slow-rolling generational realignment we’re experiencing takes hold, and it has accelerated as the country (or at least the vaccinated half) emerges from the pandemic and begins to confront the trauma we have lived through. Our social, racial and economic inequalities have been on full display, and it is altering the way many people look at the social contract, rejuvenating positive attitudes about government that have been dormant for over four decades.

These changing attitudes are reshaping the political calculus. Moderate Democrats know their Republican opponents are going to tar them as tax-and-spend socialists, but that didn’t stop them from advancing the Biden plan. It’s not just because the measures in the package are popular – so is voter protection, but that’s proved to be a more difficult lift. It’s because Democrats believe the attacks won’t work this time. They are operating under a new paradigm that assumes their constituents will reward them for supporting expansive government policy financed by the very rich.

Of course, the reconciliation package is far from a done deal. The $3.5 trillion budget target has to be formalized by the Senate, then the difficult business of determining what’s in the bill will commence. Those details could strain the Democrats’ paper-thin majorities, and it’s going to be a huge legislative challenge to assemble a package that can pass the Senate with every Democrat on board. But even if things fall apart, we have already seen the party agree on a policy blueprint that is unprecedented in our time and all the more impressive for the fact that every caucus member had to be on board.

The days are over when Republicans can frighten Democrats into running away from the kind of bold social policies that long ago defined the party. We may or may not be at the point where those policies can become law – that’s something we’ll know soon enough – but what happened in the Senate last week overturned a decades-old legislative paradigm. As generational change continues, Democrats will eventually have larger majorities to work with — provided we have free elections where everyone has a chance to participate — and the kind of legislating that was once impossible and is now a struggle will become standard. Republicans know this too, which is why they are so determined to forestall the establishment of this new majority by any means necessary while they still can.