Wander the twinkling streets of Manhattan in this holiday season and marvel. Not at the wondrous store windows, dressed-up partygoers and festive music out of every speaker. To those used to it, the spectacle repeats every December. The marvel this year is that the celebrating crowds, thicker than ever, are seemingly oblivious to the dangerous chaos enveloping the national security apparatus.

This is the city devastated by the 9/11 attacks. It remains in the crosshairs of terrorists wanting to do America great harm in the most theatrical manner. This is where the international media live to record mass tragedy against a dramatic backdrop. And it’s where a dense population enables evildoers to kill bystanders in large quantities.

The scenes of traditional revelry are really a tribute to Americans’ unique sense of security. Visitors and residents alike are going about their holiday shopping, business as usual. The question is whether this belief that we are covered remains warranted. Is the assumption that we will survive the chaos coming at us in battalions realistic?

So much of the previously unthinkable has been done by President Trump that it is not impossible to imagine that he might regard a terrorist attack as a useful distraction. Recall how Americans coalesced around President George W. Bush in the shocking aftermath of 9/11.

We’re not saying that Trump would actually stage one. But his announced troop withdrawal from Syria — causing his highly competent secretary of defense, Jim Mattis, to resign in protest — opens new opportunities for the Islamic State.

Yes, ISIS has been beaten back, but no, it hasn’t been defeated. This pullout gives it a reprieve. It also empowers our adversaries in Russia, Iran and Turkey — while betraying Kurdish allies fighting in Syria. The alarm being expressed by Republicans, as well as Democrats, adds to an air of foreboding. Our allies around the world are astounded, fearful that Trump is remaking the world in his unstable image.

Normally, a crashing stock market would capture people’s attention. That the walls are closing in on the unsavory activities of the Trump family business has become almost an afterthought — though undoubtedly standing front stage center for Trump. Could it be that Trump threw in talk of a government shutdown to move the focus elsewhere? It could.

The generals on the news channels are mulling the possibility of a wag-the-dog scenario whereby Trump attacks another country to divert attention from the chaos enveloping him. Recall the line from the 1997 movie “Wag the Dog”: “Remember the Maine … Tippecanoe and Tyler Too … they’re war slogans, Mr. Motss. We remember the slogans. We can’t even remember the f—ing wars. You know why? That’s show business.”

But suppose the dog wags us. Wouldn’t that be as useful? Now would be the time for our enemies to hit us — a cyberattack would do — as the White House trashes the intelligence agencies and as the finest military minds quit the administration. We’ve almost forgotten that chief of staff John Kelly, a retired four-star Marine general who imposed order in the White House, is also leaving.

Many of us have been reluctant to let antipathy toward Trump the man feed our wild imaginings. But responsible voices are now wondering out loud about what leverage countries other than Russia — Turkey, for example — hold over Trump personally.

In New York City, the hope remains that our ambassadors, military officers and the amazing police department can keep a lid on things. Managing security for the New Year’s Eve blowout in Times Square is a mammoth undertaking in the most uneventful times.

This year, the miracle on 34th Street may be that nothing terrible has yet happened.

Froma Harrop is a syndicated columnist. Follow her on Twitter @FromaHarrop. She can be reached by email at fharrop@gmail.com.

Froma Harrop