When the definitive political history of this decade is published, Barack Obama will be the central figure, mobbed by an array of allies, adversaries, accomplishments, and failures. But it won’t be the definitive history if it doesn’t give nearly equal treatment to the 2010 midterm elections.

The Republican victory that year was decisive enough to place nearly all of Obama’s legislative ambitions out of reach, and lock the country into an austerity cycle that acted as a choke collar around the neck of the economic recovery.

At the federal level, it carried immense significance. But as MSNBC’s Benjy Sarlin explains in this excellent primer, the consequences were if anything more severe at the state level. By sheer coincidence, the first Republican wave in nearly two decades coincided with the decennial Census, allowing the victors not just to enact conservative policies in states they wouldn’t normally have dreamed of controlling, but, through redistricting, to lock those majorities into place for many election cycles into the future. They made the Republican House majority invulnerable to an Obama re-election juggernaut in which the public at large expressed its desire for a Democratic majority by a million-vote margin. And they clustered in-state Dems into districts so lopsided that, absent a Democratic wave or a different, unlikely forcing mechanism, they can safely retain control of key state legislatures in perpetuity.

Under the circumstances, you can’t blame Democrats for plotting revenge.

The fantasy scenario for Democrats, if all goes right, might look something like this: President Hillary Clinton, capitalizing on a solid first term, a still-divided GOP, and the usual advantages of incumbency, leads her party to a decisive victory in 2020. Riding her performance, Democrats down the ticket take over a number of key state legislatures and governor’s seats. Now with far greater control over the redistricting process, they put the House back into play.

I’ve spoken to a handful of Democratic operatives about this, too, and, as Sarlin suggests, they all understand that the point of thinking ahead so far is to be prepared, not to convince themselves that the alternating political dynamic that has defined the past six years will necessarily hold for six more.