In 1885, an up-and-coming Ph.D. student named Woodrow Wilson wrote the book that would establish his academic reputation. Entitled “Congressional Government,” Wilson’s conclusions reflected “the declining prestige of the presidential office” in the decades following the death of Abraham Lincoln.

“That high office has fallen from its first estate of dignity because its power has waned,” Wilson wrote in his introduction. “And its power has waned because the power of Congress has become predominant.”

What gives Wilson’s 133-year-old musings on the American political system contemporary relevance is the Potemkin presidency of Donald Trump.

Not since Warren Harding (who preferred late-night poker games and drinking to governing) and Calvin Coolidge (who was paralyzed by depression after the death of his 16-year-old son) has there been a president as disengaged as Trump.

The reality of a president who has gone AWOL has been masked by Trump’s trick-or-tweet Oval Office style. By dominating the news cycle with his feuds and fulminations, Trump conveys the false impression of an activist president.

Trump’s claim that he is a “stable genius” brings to mind the scene in “Sunset Boulevard” when half-forgotten silent movie star Norma Desmond insists, “I am big. It’s the pictures that got small.”

The most telling recent story about the lackadaisical nature of the Trump White House came not from Michael Wolff’s over-hyped book, but from a scoop by Jonathan Swan of Axios. After seeing copies of the president’s recent private schedule (which is different from the misleading version released to the press), Swan reported that Trump normally holds his first meeting of the day at 11 a.m. before calling it quits around 4 p.m.

Watch: Hastings Responds to Trump Shutdown Tweet — Put it ‘Under His Pillow’

Less is more?

A strong case can be made that — given Trump’s disinterest in substance and his temperamental unfitness — the less that he does as president, the better off we all are. By this standard, Trump should be encouraged to play golf until his hands are blistered and to watch Fox News until his eyes can no longer focus on the screen.

Trump is not Ronald Reagan, who provided firm ideological guidance to his staff even as he delegated many of the details. Also, there is no one in the Trump White House remotely on par with James Baker, Reagan’s first chief of staff.

During the Senate debate over Obamacare and congressional passage of the tax bill, there is no indication that Trump’s purported deal-making abilities swayed a single GOP vote. In fact, in the run-up to the Obamacare vote, Trump’s heavy-handed threats to Alaska Sen. Lisa Murkowski (delivered by Interior Secretary Ryan Zinke) boomeranged.

Immigration has been a Trump obsession since he began his campaign by railing against Mexican “rapists” supposedly slithering over the border. But other than building his Great Wall of Trumpdom, there has been almost no consistency to the president’s public statements on this issue that passionately arouses his nativist supporters.

Trump’s 50-minute televised White House meeting Tuesday with a bipartisan congressional delegation represented another double-jointed performance by an acrobatic president who can’t seem to recall what he said about immigration last week or the week before that.

Suddenly, comprehensive immigration reform and a path to citizenship are on the table. Granted, the offer was accompanied by untenable Trump demands for the border wall, the end to the visa lottery system and the termination of efforts to give preference to family reunification.

But does anyone really believe that Trump’s call for the passage of “a bill of love” will last longer than the president’s next hateful tweet?

The unalterable truth — which should be recognized by congressional Republicans as well as Democrats — is that it doesn’t matter what Trump thinks. Unless there is evidence (and right now there is none) that Trump will use his veto power to torpedo congressional legislation, the Oval Office weather vane serves mostly as a distraction.

There is a power void in Washington. And, as Woodrow Wilson grasped in the 19th century, Congress is the only institution that can fill it.

This is not one of these mushy appeals for the spirit of compromise to wash over everyone on Capitol Hill from Ted Cruz to Bernie Sanders. The poisonous partisanship of Mitch McConnell (see Garland, Merrick) makes the Senate majority leader’s sudden appeals for bipartisanship seem more like comedy than comity.

Position of strength

The Democrats, who presumably will be in a stronger legislation position after the 2018 elections, are under no obligation to cut deals with McConnell and Paul Ryan for the sake of appearances or as a short-term political gambit.

But if compromises can be worked out — without abandoning major points of principle — on issues like immigration and infrastructure, then the nation should be grateful for a reassertion of congressional power. Far better that elected legislators, rather than Trump Cabinet members, set the rules on offshore oil drilling and marijuana enforcement.

In the months ahead, the Democrats might take inspiration from these lines from John Kennedy’s stirring inaugural address: “So let us begin anew — remembering on both sides that civility is not a sign of weakness, and sincerity is always subject to proof. Let us never negotiate out of fear. But let us never fear to negotiate.”

In “Congressional Government,” Wilson identified the inherent weakness of the presidency: “Because candidacy must precede election … the shoals of candidacy can be passed only by a light boat.”

The Trump presidency represents a very light boat weighed down by a very heavy ego. That is why the choice is three more years of loud-mouthed drift or Congress belatedly placing its collective hand on the tiller.