WASHINGTON — Two contradictory forces have tied up legislation in Washington for most of 2021. One is centripetal, pulling policy toward a bipartisan center, represented best by the physical infrastructure bill that the Senate passed in August but that has languished in the House. The other is centrifugal, pulling policy toward the respective political parties’ extremes.

On the Democrat side, it has been the President’s Build Back Better (BBB) bill and its $3.5 trillion price tag. On the Republican side, it is their refusal to help pass new debt limit legislation, even though they bear some responsibility for the deficit and know that a United States default is not an option.

The logjam these contradictory forces created may have begun to break up on Nov. 5, when the House passed the physical infrastructure bill — estimated at $1 trillion of spending on roads, bridges, broadband, climate-change adaptation and transit over the next 10 years — with the help of 13 Republican votes and only 6 Democrat defections. President Joe Biden had worked the phones to bring this about and will sign it into law.

Part of the deal that unstuck this measure was agreement from centrist Democrats in the House to vote for a pared down BBB bill once its estimated $1.85 trillion cost has been scored by the impartial Congressional Budget Office. The Build Back Better bill contains spending plans of various lengths on child care, health care, climate change, family leave and drug pricing. It also contains new tax provisions for larger corporations and wealthy individuals intended to offset some of its costs. It has been pared back from its original $3.5 trillion size in efforts to gain support from Senator Joe Manchin of West Virginia.

President Biden’s initial proposals for tax-rate increases on corporations and on individual incomes above $400,000 were replaced by the current tax ideas in response to Senator Kyrsten Sinema’s objections to higher individual and corporate tax rates.

Many hurdles remain for this “social infrastructure” measure to become law. There are questions about whether the measure pays for itself, as President Biden has insisted, and whether some of the tactics used — like authorization of new programs for only a few years to keep estimated costs down even though the expectation is that the programs will continue — will be accepted by centrist members of Congress. As well, it is unclear whether Senators Manchin and Sinema will find the changes that have been made good enough to earn their votes, and some possibility that more progressive members may object to the concessions made to date, such as on family leave.

With no Republican Senator yet having expressed willingness to support this bill in some form, the Democrats cannot afford to lose support from any in their party.

Hanging in the background is the issue of lifting the debt ceiling. In the past this has led to political brinkmanship, including government closures. In the end, however, a solution has been found. Senator Mitch McConnell has said so far that it will be up to Democrats to find the votes within their own party to avoid default. This could well play into the drama around efforts to pass the Build Back Better bill.

Not all of the pressure and conflicting forces have been playing out in Washington. One major international backdrop has been the Conference of Parties 26, the United Nations-sponsored conclave in Glasgow, Scotland, seeking further commitments to mitigate climate change.

National leaders from various countries — but not all of the major polluters, like Russia and China — have offered pledges to wean their economies off of fossil fuels by various dates in the future, ranging from 2030 to 2060. This has not satisfied most of the protesters demonstrating outside the conference hall, many of whom are quite young. Unlike the national leaders who gravitate toward modest or centrist stances, these young protesters are trying to pull politicians toward more drastic actions, right now. Their frustrations may have far-reaching political consequences going forward.

In several local elections within the United States, ranging from statewide offices in Virginia and New Jersey to local referendums like the race for Mayor in New York or to “defund the police” in Minneapolis, the same interplay of forces can be seen. Most of the outcomes seem to point to a growing preference for centrist policies and candidates over the more progressive agendas and candidates.

This apparent message will potentially carry over to the 2022 midterm elections, and it also will likely overhang the deliberations in the House starting the week of Nov. 15 and subsequently in the Senate over the Build Back Better bill. In perhaps its simplest terms, there is a mounting sense among many political pundits that it is more important to get some things done on pressing issues over legislating to some peoples’ ideal preferences.

Still, it seems unlikely that the House’s Progressive Caucus and President Biden will readily pare back their goals with respect to some of the more controversial issues, like clean energy mandates, immigration reform and paid family leave. All are goals that were prominent in the 2020 presidential election, whether or not they were what brought record numbers of voters out on both sides. Nor does it seem likely that Senators Manchin and Sinema will be easily moved off of their opposition to the size and funding ideas behind the progressive agenda. And Republican leaders seem unlikely to offer any further compromise ideas, instead hoping that the political winds have begun blowing back in their favor.

All of this makes for an interesting late fall in Congress. President Biden, House Speaker Nancy Pelosi and Senate Majority Leader Chuck Schumer have staked their political reputations on pulling their Democrat party together. Centrist Democrats in the House promised to vote for the BBB Act, if the Congressional Budget Office says it pays for itself. And the progressives have promised to try to strengthen some of its features, clawing back some of the compromises made.

Without much Republican cooperation, it likely leaves the United States without much bipartisan governance in the wake of the physical infrastructure law and much uncertainty over whether the Democrats can find a way to govern on their own.