OPINION — When Donald Trump declares his candidacy for a second term Tuesday night in Orlando, the line of supporters fighting to get in will stretch from Disney World to the Everglades.

Many people are already saying that Trump is such a favorite for re-election that all 23 Democrats will withdraw after they make fools of themselves criticizing the Greatest Economy in World History during next week’s debates. Already, there is a huge movement to repeal the 22nd Amendment so Donald J. Trump can be anointed as President for Life.

Sorry about that, I got caught up in Trumpian hyperbole. And have I told you that Trump Steaks are the best in the world?

In truth — despite Tuesday’s expected explosion of hoopla and hokum — the current omens are not looking propitious for the 45th president. Everywhere Trump turns, there are slights and dangers.

Do you think that Trump failed to notice that Vladimir Putin spent the weekend in Tajikistan with Chinese leader Xi Jinping? Not only did they celebrate Xi’s birthday with gifts, but Putin also continued his recent lovefest by again calling his Chinese compatriot his “dear friend.”

Trump and Vlad were supposed to be BFFs. Now Putin is stepping out on Trump with the leader of a country that won’t even play fair with trade. No wonder Trump whined in his interview with ABC’s George Stephanopoulos, “Nobody’s ever been treated badly like me.”

The ABC interview was a rare foray for Trump outside the safe space provided by Fox News. Rather than attracting attention for the novelty of Trump being interviewed by someone tougher than Sean Hannity, the Sunday night broadcast attracted meager ratings, finishing third in its time slot.

Trump, of course, will blame the ratings on the mainstream media and its loss of credibility over purported “fake news.” Or maybe the president will conclude that viewers were turned off and tuned out after hearing Mick Mulvaney, the White House chief of staff, coughing in the background.

But the ABC ratings may be symptomatic of a larger malaise facing Trump — he has become predictable and boring.

He is the Johnny One Note of politics, with his range limited to high-decibel insults and overly capitalized tweets. Trump’s targets may change, but the bombast and the shameless lying remain constant.

As a weak leader on the international stage, Trump constantly risks losing control of events. His murderous pen pal in Pyongyang, Kim Jong Un, retains the ability to humiliate Trump by resuming nuclear testing or provocatively launching a few long-range ballistic missiles over the Pacific.

Iran lurks as the true threat to Trump, the one spot on the globe where America could blunder into a major war with devastating geopolitical, humanitarian and political consequences.

Trump doesn’t understand much about international affairs (aside from promoting his golf resorts), but he does grasp that the unnecessary Iraq War had devastating consequences for George W. Bush. Trump’s problem is that he fired all the senior Cabinet members, like Defense Secretary James Mattis and Secretary of State Rex Tillerson, who shared his sense of caution about another Middle Eastern war.

So Trump is now facing a possible military confrontation with Iran in the Strait of Hormuz with no safety net: his top advisers (John Bolton, the national security adviser, and Secretary of State Mike Pompeo) are so hawkish that they make Dick Cheney look like a peacenik. And Trump’s penchant for leaving Cabinet posts vacant so that acting officials can dance on a string means that the Pentagon is effectively leaderless.

For all the pyrotechnics about immigration, Trump’s re-election campaign is based on a strong economy and a soaring stock market. With the unemployment rate at 3.6 percent, any president would be entitled like Trump to crow about the economy without crediting his predecessor.

The problem is that, with the best economy since 9/11, Trump’s approval rating is mired in the low 40-percent range. While you can cherry-pick individual polls (as Trump does with abandon), the averages compiled by RealClearPolitics and FiveThirtyEight show only small variations over the past year. And what has remained unchanged is that more than 50 percent of the voters disapprove of Trump’s performance in office, despite the economy.

Yes, you can be elected president while losing the popular vote, as both George W. Bush and Trump himself have demonstrated in this century. But political consultants are not normally in the habit of advising clients to begin their re-election campaigns with half the electorate in unyielding opposition.

Trump, with his keen survival instincts, must sense his time of troubles. That may explain why the president unexpectedly announced to Stephanopoulos that he would be unveiling a new health care plan within two months that will be “less expensive than Obamacare by a lot.”

In all likelihood, that health care plan is as elusive as the secret deal with Mexico that will solve the border crisis. But now Trump faces two unappealing choices — trying to defy history by competing with the Democrats on health care or admitting once again that his policy pronouncements have all the substance of a barstool blowhard.

If you follow only a few details about 2020 politics, these are the facts that should lodge in your brain.

Winning campaigns do not fire most of their pollsters 17 months before the election, as Trump just did. And most leaked polls in presidential politics do not show the candidate who paid for the surveys losing by double digits in key states.

So let Trump revel in the Fantasyland of his Orlando rally Tuesday night. It could be the high point of his re-election campaign.