Though only halfway over, the Virginia General Assembly session is already one for the history books.

As The Post’s Greg Schneider, Laura Vozzella and Patricia Sullivan reported, Virginia Democrats have put their trifecta control of state government to immediate use, passing legislation that unravels “years of Republican leadership and change[s] course on significant issues.”

The extent and the speed of the changes exceeds any that have occurred in Richmond since Mills Godwin’s first gubernatorial term more than half a century ago.

But even that comparison really doesn’t capture how far Democrats have shifted the policy debate.

The Virginia Mercury’s Graham Moomaw may have said it best. The General Assembly:

… passed bills to raise the minimum wage, let local governments remove Confederate statues, transform the energy landscape in response to climate change and grant legal driving privileges to undocumented immigrants.

And that was just Tuesday.

A majority in a hurry? You bet, especially on the House side, where Democrats puttered on the sidelines of power for a generation.

While some of Virginia’s once-immovable political objects, such as gun rights, appear to have been catapulted into the sea, it’s worth remembering a fundamental truth:

Sic transit gloria mundithus passes the glory of the world.

Or to put it far less poetically, even Virginia’s hyperactive Democratic majority can’t escape political gravity.

The fall to Earth may not happen for many years. Republicans, after all, managed to retain their grip on the House, and often the Senate, despite serious internal divisions (the 2004 split over tax hikes being one of the ugliest), scandals (here’s looking at you, former governor Robert F. McDonnell), hubris (Ken Cuccinelli II, call your office) and so much more.

A starry-eyed partisan will say the GOP was able to overcome all that for so long because voters were still a center-right bunch who preferred Republican control to anything Democrats might offer.

Oh, and gerrymandering. That helped a heckuva lot, too (and yes, Democratic officeholders, House and Senate alike, were as cynically careerist as their Republican colleagues when the district maps were drawn).

And let’s not forget the most powerful get-out-the-vote tool Republicans ever had: former president Barack Obama.

While Obama may have twice won the commonwealth’s electoral votes, he and the national Democratic Party were the ideal foils for local Republicans, who used them to build, if only temporarily, a veto-proof House majority.

Republicans were riding high, even as their string of statewide defeats grew, and fratricidal contests such as the U.S. House primary between then-House Majority Leader Eric Cantor and upstart Dave Brat robbed the party of its leadership and financial resources.

All that aside, and barring a black swan event such as, say, a weird presidential election, Virginia Democrats could keep swinging their chairman’s gavels in the General Assembly for a few more years.

President Trump will never be confused with an elegant swan. But whatever your favorite characterization of him may be, there’s no question his 2016 victory almost crushed Virginia Republicans.

Only the luck of the draw kept them in power in 2017. But nothing could prevent their fall from gaining momentum after the 2018 midterms, reaching its end in 2019’s General Assembly elections.

Whether Republicans will burrow even deeper come this November or somehow enjoy a dead-cat bounce that sees them briefly regain a fraction of what they’ve lost is an open question.

For General Assembly Democrats, the political woes and emotional despair of Virginia Republicans is beside the point. They are still racing against the session clock to finish the historic work they’ve begun. Once that’s done, then, maybe, they’ll turn their attentions elsewhere.

That’s entirely fair and to be expected. But Democrats should not forget the GOP example before them. Political majorities are temporary, and some of the bills Democrats pass today could be repealed three, 10 or 20 years from now.

Sic transit gloria mundi.