More than half the states have voted and the presidential candidates are entering the home stretch of the nominating gantlet. But up to now, they have been ignoring a mighty special interest: events.

Events have a vote, as the terrorist attacks that rocked Brussels reminded us. The bloody strike at the heart of Europe, not far from the headquarters of the European Union and NATO, delivered a powerful punch that could reshape the race for the White House.

In the instant aftermath, there is little doubt that Republicans in general, and Donald Trump in particular, will get a boost. After all, Trump has been the most aggressive of all the surviving candidates, calling for a temporary ban on Muslims, tougher border controls and stepped-up interrogation techniques for enemy detainees. In January, he actually singled out Brussels as a potential problem, calling it a “hellhole” because of the large number of unassimilated Muslims.

He was ridiculed, of course, but events now make him look prophetic while Democrats are stuck defending a failed status quo. Hillary Clinton’s comments yesterday reflected the trap, as she tried to talk tough without actually saying anything that would challenge current White House policies: “Today’s attacks will only strengthen our resolve to stand together as allies and defeat terrorism and radical jihadism around the world.”

She might have added, “Blah blah blah.”

As for President Obama, imagine if he were seeking re-election instead of a legacy. In that case, he would have raced home from Cuba as soon as he understood the scope of the European horror to assume the image of an engaged commander-in-chief and assure his countrymen that their government was on guard.

Instead, safe from voters for the rest of his life, he was content to mouth a few platitudes about sympathy and solidarity with Brussels, then stick to his script in Cuba as if nothing had happened. His boast that “I have come to bury the last remnant of the Cold War” seemed especially hollow, given the gory images of mangled bodies emerging from the scene.

In light of a revived Russian bear on the march in Europe and a hot war with Islamic terrorism spreading around the world, Obama’s self-aggrandizing claim painted him as frighteningly out of step with events.

His callous indifference is not new. Back in August 2014, Obama briefly interrupted a Martha’s Vineyard vacation to express horror at the video beheading of American journalist James Foley. Within hours, the president was on the golf course, yukking it up with friends.

As I wrote at the time, “Simple decency and respect for Foley’s horrified parents should have been enough to sober him. If that didn’t do it, the realization that the Islamic State had declared war on America in the most gruesome fashion imaginable should have sounded a call of duty in his head.”

But, much as he played golf then, Obama continued on his glory tour of Cuba Tuesday. In neither case, or in any case ever, has he dared call Islamic terror what it is. For him, it is always just “terrorism” or “extremism.” Blood and facts have not softened his resolve to never speak the religious truth about the barbarians.

Unfortunately, reality is not cooperating with his fantasy. The Islamic State, which Obama infamously derided as the “jayvee team,” is a terrorist army controlling a broad swath of land in Iraq and Syria it calls a caliphate. Its reach is spreading, as proven by the attacks from Paris to San Bernardino, and now Brussels.

No less than a former member of Obama’s team, Michael Morell, who twice served as acting CIA director, told CBS that the group now controls “more territory today around the world than they did at any time.”

“So I would say they’re winning, right? They’re winning,” Morell said.

Obama’s mantra has been that America was war-weary, and he would be rewarded for shrinking the nation’s military footprint. While there was some truth to his idea, I have always believed most Americans are not so much war-weary as they are tired of losing wars. And they certainly are tired of living in fear.

If true, then the next president will likely be the candidate who can convince the most voters that he or she can make the nation safe and a winner again. Think of it as a national-security primary, with events in Brussels offering a clear contrast of the candidates’ strengths and weaknesses.

So far, it’s advantage Trump.

‘Shel’ race looks shady

The Post’s reports on the lower Manhattan race to succeed the disgraced Sheldon Silver in the Assembly suggest something fishy is going on. How predictable!

Silver’s pals in the local Democratic club nominated Alice Cancel for the special election next month, but she’s been invisible and reports raising under $4,000.

Meanwhile, the candidate of the Working Families Party, Yuh-Line Niou, has been very active and raised $144,000.

Niou initially challenged Cancel for the Dem nomination, but suddenly withdrew and switched to the Working Families Party ballot line. The two parties are often united and endorse the same candidate, with the WFP little more than a union front helping to elect Dems.

My hunch is that there is a secret non-aggression pact between the parties this time so they don’t divide the liberal vote and make way for the credible Republican candidate to win the seat. Lester Chang, a Chinatown businessman and naval reservist, is on the GOP line and has the support of former Mayor Rudy Giuliani.

Whatever the circumstances, it would be fitting if Silver’s conviction on corruption charges led to a Republican successor. Justice and the neighborhood would be best served by having an untainted representative in Albany.

Blas rent ‘win’ may be fixer-whopper

Mayor Bill de Blasio will be showered with praise by his allies for getting his affordable housing plan through the City Council, but I remain skeptical about the real-world impact.

The requirement for more lower-rent apartments to be included in new developments and to allow bigger and taller buildings in residential neighborhoods could backfire.

The measure could mean better housing for more people, or it could squelch new construction because the terms for builders are too onerous and the buildings too imposing.

Either way, the city will be on the hook for increased expenses.

De Blasio made the program a centerpiece of his campaign, so delivering the deal counts as a political victory. But now comes the hard part of actually delivering quality housing for the poorest New Yorkers. I’ll save my congratulations until the tenants move in.

Moon ‘shine’

Headline: “Tourist resort on moon will offer constant sunshine.”

That can mean only one thing: Somebody’s going to make a mint selling sunscreen.