OPINION — Donald Trump’s next State of the Union Address will be delivered in the shadow of the Iowa caucuses and the New Hampshire primary. It will be a time when the spirited race for Democratic nomination will offer more drama than the president’s tricks and tweets.

And if the Democrats win back the White House, that 2020 speech will have been Trump’s last State of the Union, since defrocked presidents, even ego-mad ones, rarely make the inaugural year trek to Capitol Hill to read their own political obituaries.

Trump’s Tuesday night bloviation-a-thon (which almost broke Bill Clinton’s don’t-stop-talking-until-tomorrow State of the Union record) has been described as the opening salvo of his 2020 re-election campaign. But what it really represented was Trump’s weakened position as he contemplates a second four-year term in a White House that he probably wishes had more gold faucets.

For all the heavy-handed leaks from presidential aides that the speech would be an uplifting appeal for “unity,” Trump demonstrated yet again that he is unable, even with a teleprompter, to sustain a conciliatory tone for more than 20 minutes. All it took to spoil the mood was Trump’s denunciation of “ridiculous partisan investigations” and his ridiculous claim, “If there is going to be peace and legislation, there cannot be war and investigation.”

To use a 19th-century circus term, Trump is a one-trick pony.

No matter how fervently Republicans wish that Trump in his eighth decade would miraculously grow in office, he will always remain the bilious billionaire of the 2016 campaign.

Judging from Tuesday night’s speech, Trump seems poised to borrow his campaign slogan from 1950s British Prime Minister Harold MacMillan, who boasted that the voters “never had it so good.” In Trump’s telling, he is the mastermind behind the greatest economy since the Egyptian pharaohs went on a pyramid-building spree.

While some of Trump’s braggadocio about the economy was as hyperbolic as his real estate brochures, there was an element of truth to his pointing with pride. As Trump put it, “Unemployment has reached the lowest rate in over half a century.”

In truth, the lowest annual unemployment rate (3.5 percent) since the Korean War was achieved in 1969, the first year of Richard Nixon’s presidency.

Even though more than 11,000 American soldiers died in Vietnam that year, Nixon’s approval rate still bounced between 55 and 65 percent. The months before the 9/11 attacks were another a period of near-record low unemployment — and both Clinton and George W. Bush were rewarded with approval ratings above 60 percent.

Presidential popularity has always been closely linked with the health of the economy. But in contrast to Nixon, Clinton and Bush, Trump’s approval rating is roughly where it has always been — bumping along just a shade above 40 percent.

Why does anyone believe that things can get better politically for Trump by the 2020 election? If prosperity and the perception of peace cannot close the deal with three-fifths of the electorate, what else will Trump have going for him?

According to the Gallup Poll, a strong public consensus against Trump’s Great Wall of Politics has remained roughly unchanged from June 2018 until the end of January. While there is no reliable polling yet on the State of the Union (overnight surveys are cable TV clickbait), nonstop Trump demonology about caravans approaching the Rio Grande, terrorists sneaking across unfortified border crossings and immigrant gangs running wild in the streets have failed to move the needle.

It should be remembered that Senate Republicans are increasingly reluctant to come to Trump’s rescue. With GOP Senate seats potentially in jeopardy in 2020 in Colorado, Arizona, Maine and (if Stacey Abrams runs) Georgia, political self-interest argues for imperiled legislators to step back from an uncritical embrace of an unpopular president.

Mitch McConnell — the human weathervane — recently told the White House that he can’t provide a Senate majority if Trump declares a bogus national emergency at the border. And McConnell is also talking about passing compromise legislation to avoid another government shutdown, even if there is no guarantee that Trump would sign it.

With an empowered, iron-fist Nancy Pelosi ruling the House and skittish Republicans clinging to a Senate majority, Trump will soon discover that, in legislative terms, he is already a lame-duck president. Devoid of the power to persuade and lacking the ability to credibly project fear, Trump’s arsenal will be limited to the veto.

Then there is Robert Mueller and the other federal investigations of all things Trump. While only soothsayers with the unerring vision of Rudy Giuliani dare predict the pace and the outcome of the Mueller investigation, Trump is unlikely to ever benefit from a national wave of sympathy over his tragic victimization by a “witch hunt.”

It is an article of faith among Republicans that “Democrats in Disarray” will become a major headline leading into the 2020 campaign. But with the sudden exception of Virginia, it is impossible to find credible evidence that the Democrats have embarked on a mutual suicide mission.

Although in different fashion than he intended in the State of the Union, Trump has given the Democrats that most precious political gift — unity. A recent Monmouth University national poll found that Democrats, by a hefty margin, prefer a presidential nominee who could beat Trump over one who checked all the right boxes on ideological issues.

When Trump reviews the history of what will probably be his single term in the White House, he may look back on State of the Union night 2019 and say, with a tinge of sadness, “I never again had it so good.”

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.