If Republicans aren’t losing their congressional majority this coming fall, they are doing a good job of acting like it.

Dozens of Republicans are leaving the House in an epic exodus, and last week Paul Ryan said he is resigning as House speaker at the end of this Congress, and won’t even run for his congressional seat again.

If the high-water mark of Republican power came on the day last December that congressional Republicans and President Trump celebrated the passage of the tax bill on the White House lawn, Ryan’s announcement is a clear sign that Republican clout has begun to recede.

“We Were Eight Years in Power: An American Tragedy” is Ta-Nehisi Coates’ lament over what he considers the lost opportunity of the Obama years. It may be that the story of unified GOP control of Washington will someday deserve to be written as, “We Were Two Years in Power: A Tragicomedy.”

In a gift for the ages, Republicans won all elected branches of the federal government in 2016. They had no reason to expect Trump to win the presidency, and, in fact, very few of them expected it. The initial ecstasy over Trump “signing their stuff” has given way to the reality that they don’t have stuff to send him.

Republicans couldn’t roll back ObamaCare, in part because the party hadn’t thought through what the Republican alternative was — even though anyone could have known this would be the central question if the GOP ever got a legitimate shot at repeal.

They passed a tax cut that included important reforms that even the Democratic repeal bills don’t want to completely undo and that are boosting the economy.

That’s all to the good. But tax cuts aren’t a magic political elixir.

First, Trump is right, as he said at an event a couple of weeks ago when he tossed away his script, that they are boring. They don’t have the emotive appeal of issues like trade and immigration. Second, there are limits to how effectively you can run on the one big thing you accomplished last year (and as of this November, it will be almost exactly a year ago).

This is the truly extraordinary aspect of the current situation. Republicans are content not to do anything else of significance in Congress this year. They passed an omnibus spending bill that was rightly denounced as a disgrace by Trump even as he signed it, and the Senate is working to confirm Trump appointees.

That’s pretty much it.

They aren’t trying to wring every last ounce of what could be their waning months of unified control of Washington — for years to come. They aren’t determined to give their voters some other reasons to support them in November. They aren’t attempting to create other action in Washington besides Trump’s escalating feuds with Robert Mueller, James Comey and Stormy Daniels.

Republicans are resting on their laurels, when they don’t deserve any laurels. They are suffering from political exhaustion, when they haven’t truly exerted themselves. They are acting like they are lost in the wilderness, when they still occupy the commanding heights of American politics.

The Democratic majority in the run-up to 1994 had this autumnal feel, but it had been in power for decades and was running on fumes. The Republican majority, held at bay for six years under President Barack Obama, should be feeling its oats rather than stumbling toward the exits.

This is, in large part, a result of the bizarre circumstances of the GOP sweep in 2016. The party showed every sign of being on the verge of defeat amid a major identity crisis. Its establishment was ineffectual, its old verities up for grabs, and its voters in revolt.

But instead of losing, the party won despite — or maybe because — of its identity crisis.

That crisis is not nearly as obvious as it would have been in the event of a Trump defeat, but it hasn’t been conducive to governing.

The old Republican limited-government congressional agenda has less purchase in the era of Trump, while the president’s populist-nationalist impulse hasn’t come close to being refined into an actionable legislative program. Instead, it has been expressed almost exclusively through executive actions and in his speeches and Twitter feed.

Maybe Republicans will somehow hold on to the House this fall (the generic ballot is encouraging lately, if nothing else is). There’s no doubt that the GOP will shed seats, though.

At the very least, Republicans are going to lose their functional majority. The question at this juncture is: How would anyone notice?