Not since Joe Biden first claimed his desk in the Senate half a century ago have either Republicans or Democrats governed the nation through more than one or two election cycles. The score in the past dozen presidential contests is a flat-out tie — six to six. Control of one or both houses of Congress has ping-ponged back and forth since the 1980s as well.

The longest stretch of partisan parity in U.S. history has trapped us in a political stalemate with little hope of breaking out. As a result, problems that have long plagued the nation — economic inequality, undocumented immigration, climate change, the undermining of democratic values — persist.

A true realignment could shake us from the festering gridlock. But what would it take for one party to dominate American politics again?

From the 1820s, when mass elections began, there have been just three periods of prolonged one-party dominance: the Democrats under Andrew Jackson and his disciples; the Republicans for long stretches from McKinley to Hoover; then the Democrats again, for extended periods from Franklin Roosevelt to Lyndon Johnson. The first was unique, fueled by a populist appeal to ordinary white male voters and support for Southern slaveholders. But each of the other two was brought on by a profound, utterly gutting economic crisis: a prolonged depression in the 1890s and another one just under four decades later.

These were consequential eras. Jackson killed the central bank, and one of his Democratic successors, James Polk, provoked a war with Mexico. During the early 20th century, Republicans enriched homegrown industries and turned the federal judiciary into a dedicated foe of unions. New Deal and Great Society Democrats embraced a growing labor movement and enacted such pillars of the welfare state as Social Security and Medicare, while moving to dismantle racism under law.

In many ways, however, our politics remain stuck in the long 1960s. Progressives and conservatives still battle over some of the big issues that roiled the nation half a century ago — affirmative action, the right to abortion, rights for gay men and lesbians, environmental protection and the content of education — with little lasting movement in either direction.

Ending our current partisan stalemate may require a crisis on the scale of those that began or ended the earlier sway of majority parties. But even without, say, a financial debacle or outbreak of civil conflict, there may be ways for a party to achieve at least short periods of dominance.