One thing we already know about 2016 is that it's an inflection point in America's national political history.

Say you're playing a parlor game where friends and family shock each other by pointing out how long ago certain things happened. To heighten the effect, maybe you draw a surprising comparison between the time frames of historic events. Or maybe you point out how short American history really is. The lives of Francis Scott Key, Henry James, and Kirk Douglas, for instance, cover American history all the way back to the Revolutionary War.

But if you really want to unnerve someone, tell them this: 2016 will bring us closer to the 22nd Century than we are to the election of Franklin Roosevelt.

At this year's midway point the era ushered in by FDR (now 84 years ago) and the tolling of the next century make for remarkable and revealing psychological milestones.

The current political season is playing out as a referendum on how long the era that began in 1932 can endure. We're still trying to figure this out. In the last presidential election year, the Post's E.J. Dionne sensed that followers of both parties, in different ways, pined for the 1950s. "For progressives, the backward-looking wish is for the shared and growing prosperity when unions thrived and could enforce a relatively egalitarian social contract," he surmised. "On the right, '50s nostalgia takes the form of a quest for order, social homogeneity, religious faith — or, at the least, public respect for traditional values — and strong families, sometimes defined as a return to old gender roles and a less adventurous approach to sexuality. Neither side fully acknowledges its own nostalgia," he allowed, "partly because everyone wants their 1950s a la carte."

But Dionne concluded that Americans' widespread discontent shared a fundamental source: a collapse of certainty in "a stable society with a growing economy." Now, we ought to recognize that 1932 marked the year that the promise of that certainty gained the upper hand in politics — because of what Roosevelt stood for, represented, and embodied.

Roosevelt, through the federal government, began to strengthen the state until the majority of Americans could place faith in the kind of national character like a towering Sequoia tree: Its success is evidence through reliable, sturdy increase, measured not in the frantic tempo of modern change but in the organic creep of something stronger. “Never in history have the interests of all the people been so united in a single economic problem,” Roosevelt told the Democratic National Convention in July of 1932. The solution to that problem was to remain just economically united — through a relationship with the national government, whose power would deepen and strengthen through time. “This nation is not merely a nation of independence,” Roosevelt concluded, “but it is, if we are to survive, bound to be a nation of interdependence.” And only the federal government had the stability and supremacy to foster and guarantee it, managing the relationship between supply and demand on the one hand and the value of money on the other. The legacy of New Deal innovations like the Agricultural Adjustment Act and the National Industrial Recovery Act long outlasted the Great Depression, economically uniting Americans of all classes by ensuring their shared dependence on the state.

But the limits to that unity have showed forth in the political paradoxes of today. Life would be unimaginably worse, for rich, poor, and middle class alike, were they to wake up tomorrow without the benefits, incentives, and protections given to them from Washington. Whether propped up by food stamps and Medicaid, student loans and mortgage interest tax deductions, or economic bailouts and big agricultural subsidies, no class of Americans seems poised to do better off with less federal assistance. Yet the great unrest that roils both parties today reflects a collapse of confidence in the stability of that arrangement. It's this unrest that explains Occupy Wall Street and the campaign of Bernie Sanders. It also explains the Tea Party and the surprising political success of Donald Trump. Everyone knows the system is rigged. People just can't figure out who the system is rigged against. The fear is palpable: not just that one basket of goodies or another might be taken away, or that the economy has been imbalanced in favor of one group of another, but that the distribution of patronage is so precarious that one wrong move could upset the whole. One stiff breeze, and its seems our towering Sequoia could tip over.

As we leave the gravitational pull of 1932, and hurl toward that of 2100, not less than the sustainability of our current form of governance is at stake. A lot is to be revealed about your deepest political feelings if you feel excitement or dread when imagining the day when the America of 1932 is as distant to us as the America of 1848 was to those who first cast their ballots for the New Deal. If history is any guide, there will be no wholesale revolution at the ballot box in 2016. But this year may well mark the beginning of the end for the era of government largesse.

The Sequoia tree probably isn't going to fall down yet, but it might be sick.