From Franklin Delano Roosevelt’s New Deal to Joe Biden’s Big F‑ing Deal, progressives have led a consistent and largely successful campaign to expand the size and scope of the federal government. Now, Matt Yglesias suggests, it’s time to take a victory lap and call it a day:

For the past 65–70 years—and especially for the past 30 years since the end of the civil rights argument—American politics has been dominated by controversy over the size and scope of the welfare state. Today, that argument is largely over with liberals having largely won. […] The crux of the matter is that progressive efforts to expand the size of the welfare state are basically done. There are big items still on the progressive agenda. But they don’t really involve substantial new expenditures. Instead, you’re looking at carbon pricing, financial regulatory reform, and immigration reform as the medium-term agenda. Most broadly, questions about how to boost growth, how to deliver public services effectively, and about the appropriate balance of social investment between children and the elderly will take center stage. This will probably lead to some realigning of political coalitions. Liberal proponents of reduced trade barriers and increased immigration flows will likely feel emboldened about pushing that agenda, since the policy environment is getting substantially more redistributive and does much more to mitigate risk. Advocates of things like more and better preschooling are going to find themselves competing for funds primarily with the claims made by seniors.

I’d like to believe this is true, though I can’t say I’m persuaded. It seems at least as likely that, consistent with the historical pattern, the new status quo will simply be redefined as the “center,” and proposals to further augment the welfare state will move from the fringe to the mainstream of opinion on the left.

That said, it’s hardly unheard of for a political victory to yield the kind of medium-term realignment Yglesias is talking about. The end of the Cold War destabilized the Reagan-era conservative coalition by essentially taking off the table a central—and in some cases the only—point of agreement among diverse interest groups. Less dramatically, the passage of welfare reform in the 90s substantially reduced the political salience of welfare policy. The experience of countries like Canada and the United Kingdom, moreover, suggests that if Obamacare isn’t substantially rolled back fairly soon, it’s likely to become a political “given” that both parties take for granted. Libertarians, of course, have long lamented this political dynamic: Government programs create constituencies, and become extraordinarily difficult to cut or eliminate, even if they were highly controversial at their inceptions.

We don’t have to be happy about this pattern, but it is worth thinking about how it might alter the political landscape a few years down the line. One possibility, as I suggest above, is that it will just shift the mainstream of political discourse to the left. But as libertarians have also long been at pains to point out, the left-right model of politics, with its roots in the seating protocols of the 18th century French assembly, conceals the multidimensional complexity of politics. There’s no intrinsic commonality between, say, “left” positions on taxation, foreign policy, and reproductive rights—the label here doesn’t reflect an underlying ideological coherence so much as the contingent requirements of assembling a viable political coalition at a particular time and place. If an issue that many members of one coalition considered especially morally urgent is, practically speaking, taken off the table, the shape of the coalitions going forward depends largely on the issues that rise to salience. Libertarians are perhaps especially conscious of this precisely because we tend to take turns being more disgusted with one or another party—usually whichever holds power at a given moment.

The $64,000 question, of course, is what comes next. As 9/11 and the War on Terror reminded us, the central political issues of an era are often dictated by fundamentally unpredictable events. But some of the obvious current candidates are notable for the way they cut across the current partisan divide. In my own wheelhouse—privacy and surveillance issues—Republicans have lately been univocal in their support of expanded powers for the intelligence community, with plenty of help from hawkish Democrats. Given their fondness for invoking the specter of soviet totalitarian states, I’ve hoped that the folks mobilizing under the banner of the Tea Party might begin pushing back on the burgeoning surveillance state. Thus far I’ve hoped in vain, but if that coalition outlasts our current disputes, one can imagine it becoming an issue for them in 2011 as parts of the Patriot Act once again come up for reauthorization, or in 2012 when the FISA Amendments Act is due to sunset. In the past, the same issues have made strange bedfellows of the ACLU and the ACU, of Ron Paul Republicans and FireDogLake Democrats. Obama has pledged to take up comprehensive immigration reform during his term, and there too significant constituencies within each party fall on opposite sides of the issue.

Further out than that it’s hard to predict. But more generally, the possibility that I find interesting is that—against a background of technologies that have radically reduced the barriers to rapid, fluid, and distributed group formation and mobilization—the protracted health care fight, the economic crisis, and the explosion of federal spending have created an array of potent political communities outside the party-centered coalitions. They’ve already shown they’re capable of surprising alliances—think Jane Hamsher and Grover Norquist. Suppose Yglesias is at least this far correct: The next set of political battles are likely to be fought along a different value dimension than was health care reform. Precisely because these groups formed outside the party-centered coalitions, and assuming they outlast the controversies that catalyzed their creation, it’s hard to predict which way they’ll move on tomorrow’s controversies. It’s entirely possible that there are latent and dispersed constituencies for policy change outside the bipartisan mainstream who have now, crucially, been connected: Any overlap on orthogonal value dimensions within or between the new groups won’t necessarily be evident until the relevant values are triggered by a high-visibility policy debate. Still, it’s reason to expect that the next decade of American politics may be even more turbulent and surprising than the last one.