OPINION — At last, a welcome burst of creativity as the government shutdown slogs towards the end of its fourth week.

In tactical terms, it was devilishly clever for Nancy Pelosi to write Donald Trump to announce that the House Democrats, in effect, will be at home binge-watching two seasons of “Mrs. Maisel” on State of the Union night.

Of course, Pelosi’s claim that she was rescinding the Jan. 29 invitation to the president on security grounds because the Secret Service is working without pay has all the credibility of a Sarah Sanders press briefing.

And while Trump’s inner psyche is a land off-limits to all but the bravest Freudian explorers, it is hard for the rest of us to imagine that Pelosi’s own shutdown will suddenly prompt the president to rethink his.

But Pelosi’s gambit brings with it an under-appreciated benefit: It reminds Trump that trampling on the unwritten norms of American democracy can cut two ways.

For two years, Trump’s approach has been that I can do anything I want unless the courts or Congress forcefully stop me.

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As a result, Trump ignored the chain of command in the Justice Department to name Matt Whitaker, an underqualified toady, as acting attorney general. He repeatedly threatened to use emergency powers, associated with wartime, to build his Ego Wall on the border without congressional appropriations.

After refusing to release his taxes, Trump has continued to buck rake from the Oval Office, as anyone seeking to curry favor with the administration — from foreign diplomats to T-Mobile executives — smartly books pricey suites at the Trump International Hotel.

And the lengthy list of violated norms pointedly includes secret aide-free meetings with Vladimir Putin — a guy whom you would not normally trust with your wallet or your democracy.

Now that the Democrats have taken control of the House, Pelosi also has political weapons at her disposal and no hesitancy about using them.

The way things were

The Constitution does not require the State of the Union to be delivered as a speech. In fact, a written message laying out the president’s legislative agenda was the norm from Thomas Jefferson through William Howard Taft.

All changed when Woodrow Wilson, shortly after he was inaugurated in 1913, sent word to Capitol Hill that he planned to personally address Congress. Concerned that the new president might feel like an interloper in the Capitol, both the House and the Senate scurried to pass resolutions formally inviting Wilson to speak on the state of the union.

Wilson’s address on the tariff issue was stunningly brief, clocked at little more than six minutes. In fact, the New York Evening World calculated that the president was back at the White House just 37 minutes after he began speaking.

In his pathbreaking address, Wilson explained that he had come to Capitol Hill to demonstrate that “the president of the United States is a person, not a mere department of government hailing Congress from some isolated island of jealous power.”

No one doubts that Trump is a person, though it is hard these days to find many who would add the adjective “praiseworthy” or even “good.” It is bizarre to watch a purported leader, who fancies himself a world-class dealmaker, demonstrate that he has no other tricks in his negotiating arsenal beyond holding his breath until he turns blue.

At the risk of seeming like I have donned partisan blinders, I don’t see how Pelosi and the House Democrats are even partly to blame for the impasse. Ever since Trump himself scuttled Mike Pence’s efforts to negotiate a funding compromise with the Democrats, the president has not made a single offer (unless you somehow count substituting steel for concrete) to reopen the government.

Blame it on the reign

Trump, as we all know, lives in his impregnable fortress of fast food and Fox News. But Mitch McConnell — pragmatic, cynical and ruthless — purports to reside in the real world. Yet it is the Senate majority leader, more than anyone other than Trump, who holds the keys to reopening the government.

If the matter could come to a vote, there is a solid Senate majority of Democrats plus Republicans like Lisa Murkowski and Cory Gardner to temporarily reopen the government while negotiations continue. But McConnell — fearful of the White House in a way that he wasn’t when Merrick Garland was nominated to the Supreme Court — refuses to bring to the floor any legislation that he says Trump won’t sign.

C’mon. No one on this planet — including Trump — is certain what the president would do if he were handed temporary funding bills. Maybe Trump would tear them up in anger. Maybe he would desperately switch on Fox News for guidance. Or maybe he would sign them while duplicitously claiming that they contain full funding for his cherished wall.

And if wailing about the wall is such a winning political position for Trump, then McConnell out of party loyalty should give the president the opportunity to theatrically wield his veto.

Speaking of theater, it is safe to assume that Trump will be speaking somewhere on the evening of Jan. 29, whether it is the Senate chamber, the steps of the Capitol or at a raucous rally in which the chants of “Lock her up” are directed at Pelosi rather than Hillary Clinton.

But if nothing else, the yanked State of the Union invitation demonstrates the enduring value of America’s unwritten Constitution — and why presidents undermine it at their own risk. Or, as Pelosi might put it, revenge is a dish best served on a cold Tuesday night in late January.

Walter Shapiro  has covered the last 10 presidential campaigns. He is also a fellow at the Brennan Center for Justice at NYU and a lecturer in political science at Yale. Follow him on Twitter @MrWalterShapiro.