In an age when doomsday predictions are as common as thunderstorms, it can be instructive to look back at events and compare the predictions to what actually happened. The decision by President Trump to recognize Jerusalem as Israel’s capital is an example that offers major lessons.

Long before Trump made the announcement on Dec. 6, 2017, and pledged to move our embassy to Jerusalem, there were endless warnings that the change would cause global unrest. Opponents in America, Europe and the Arab world, including current and former government officials, vehemently insisted the peace process between Israel and Palestinians would be destroyed. Some even warned that America would be sucked into ­another Mideast war.

Ho-hum. It’s a year later and the sky still refuses to fall. Nor is the Mideast burning.

In fact, little or nothing has changed between the parties as a result of the announcement and the subsequent embassy move from Tel Aviv. There was no peace process at the time because the Palestinians had refused even to negotiate, and that remains the case.

Also, Israel already was moving beyond the Palestinian issue and, because of threats from Iran and ­Islamic State, had established working security alliances with several Arab states, including Saudi Arabia. Those arrangements are intact and expanding, as are its relationships with China and others outside the region.

Among the lessons that hindsight affords is that conventional wisdom was simply wrong. It turns out that those supposedly in the know actually knew nothing.

A corollary is that the so-called Arab street turned out to be a ­fictional force, with the promised outpouring of mass support in Arab countries never materializing. ­Although there was grumbling and sporadic rock-throwing and tire-burning, Armageddon stayed off stage.

Another lesson is that strength creates its own advantages. Presidents who blink in a crisis, as ­Barack Obama did by failing to ­enforce his red line in Syria, invite more trouble because opponents believe they will wilt. In ­office for nearly a year, Trump had demonstrated that riots don’t move him, so riots didn’t happen.

I was in Jerusalem the day of his announcement and Israelis were jubilant. Trump was hailed as a hero for the ages because he conformed American policy to what every Israeli knows: Jerusalem is the eternal capital of the Jewish state.

That reality was why virtually every presidential candidate for two decades promised to make the embassy move — but only when the time was right. The hesitation, enshrined in a 1995 law that allowed delays, gave a heckler’s veto to ­Arabs and incentivized violence. Trump changed the pattern by ­deciding the time was right to do the right thing.

This is not to claim that all the chips fell into place and everyone lived happily ever after. Hamas, true to its terrorist nature, used the actual opening of the new embassy in May to organize attempts to crash the Gaza border fence.

Israeli troops responded with tear gas and rubber bullets, along with live fire, and shot and killed a reported 59 Palestinians. Yet despite the usual condemnation at the United Nations that Israel had used disproportionate force, Hamas ­acknowledged that 52 of the dead were militants, many of them armed.

Meanwhile, thousands of Hamas rockets have been fired at Israeli towns and kites loaded with firebombs sent across the border, starting fires that burned thousands of acres of farmland.

Some of the kites carried Nazi swastikas, according to The New York Times, a reminder about Arab hate and proof that further delay on the Jerusalem declaration would not have changed Hamas’ determination to destroy Israel.

For ordinary Palestinians in both Gaza and the West Bank, the continuing refusal of their leaders to negotiate with Israel and the Trump administration compounds years of missed opportunities. ­

Every passing day is another lost day where Palestinians could have had their own state.

Importantly, Trump’s team acknowledged the Jerusalem move meant he would tilt to Palestinians on other issues, and he pointedly did not rule out the possibility that East Jerusalem could be the capital of their state.

Yet continuing the pattern started in 2000, when Bill Clinton failed to get Yasser Arafat and then-Israeli Prime Minister Ehud Barak to create a two-state solution at Camp David, the Palestinians never get to yes.

Time and again, they walk away when a reasonable deal could be made.

Finally, an American president called their bluff and showed that even their threats were empty.

Taking & delivering punches

Scoring the punches that prosecutors throw at President Trump is a bit like scoring a heavyweight boxing match. Body blows might add up over the course of the fight, but anything that isn’t a knockout isn’t decisive.

So it was with the three sentencing memos released late Friday, two from special counsel Robert Mueller and one from Manhattan federal prosecutors.

The clearest hit on Trump came from the Manhattan feds’ memo asking for substantial prison time for Michael Cohen. Reprising statements Cohen made when he pleaded guilty, prosecutors said that, among other crimes, the former Trump fixer broke campaign- finance laws by paying hush money to Stormy Daniels and another woman, and that he acted at Trump’s direction.

The intended point is that Trump committed a felony, though how that plays out is a mystery. An indictment is theoretically possible because the deed happened before the president took office, though that effort would cause a bloody battle of its own.

The main event, of course, is Mueller and his memos on Cohen and Paul Manafort, which continue his maddening pattern of teasing about big developments without delivering. So there is more talk of Russia, Russia, Russia, but lots of redacted material and no evidence linking Trump to any “collusion,” however the word is defined.

The day, then, leaves the president battered but still standing. He’s also punching back hard, aiming to weaken Mueller and his team.

One appeal of actual boxing is a limit on the number of rounds. Unfortunately, Mueller vs. Trump looks as if it will continue long past the point of America’s endurance.

Lefty AOC takes Trump Jr.’s bait

Alexandria Ocasio-Cortez, an incoming member of Congress from Queens, foolishly responded to a tweet about socialism from Donald Trump Jr. by pulling rank. She charged that he was trying to distract from his father’s troubles, then added, “it’s definitely a ‘very, very large brain’ idea to troll a member of a body that will have subpoena power in a month.”

In her case, power doesn’t just corrupt, it corrupts instantly.

It’s ‘suppression’ in Fantasyland

Reader Harold Theurer spots an outrage that has escaped social- justice warriors. He writes: “It’s come to my attention that Disney requires photo ID in order to enter its facilities.

“Because asking voters for photo ID is considered Voter Suppression, does Disney’s rule amount to Joy Seeker Suppression?

“How interesting that walking down Main Street USA requires more scrutiny than casting a ballot.”