It’s been 17 years since Muslims – mostly from Saudi Arabia – sneaked weapons through the airport security system in Portland, Maine, then connected to other flights and commandeered four commercial jets.

They crashed them into the Twin Towers in New York, the Pentagon, a field in Pennsylvania, likely en route to the White House, and killed nearly 3,000 Americans.

The nation was in shock, wondering if another cells of jihadists was poised to strike.

Singer-songwriter-country-music icon Charlie Daniels writes that it took a little while, but the nation united as it hadn’t since the Second World War.

“The confusion turned to anger and then the anger turned to white-hot fury and America only waited for the culprit to be identified to know who to vent their vengeance toward,” he said. “Absolutely nobody would have had the guts to kneel during the playing of the National Anthem and American flags were on display everywhere.

“We were playing that weekend in Harrison, Arkansas, and I’ll never forget the sights on the drive out. Old Glory was flying from the backs of 18 wheelers, radio aerials, flagpoles and buildings and the fast food marquees all along the highway carried slogans like ‘God Bless America’ and ‘Pray for America,‘” he said.

Newspapers printed full-page flags “so people could at least have a paper one.”

The nation was “locked and loaded.”

Since then, he said, two wars have been fought “by someone else’s rules of engagement.”

And other things didn’t go so well, either.

“We had a president for eight years who started his term by bowing to the king of a country where the scumbags who flew the planes that killed nearly 3,000 Americans in one fell swoop were born,” he noted, not naming Barack Obama.

“The same president instigated a program to allow thousands from nations who hate us and had not been properly vetted to come into our country,” he wrote. “He also lifted sanctions and sent a planeload of cash to the world’s number one exporter of terrorism and drew meaningless red lines that our enemies crossed with impunity.”

So now it’s 2018, he said.

A “new president,” he noted, has “wreaked havoc on ISIS, revoked the ridiculously one-sided treaty with Iran, beefed up our military, and, so far, has stood behind the things he has said he was going to do.”

“Are we safer? I think so, in a cautious sort of way,” he said.

He said he believes the world now knows America would react with “instant and white-hot fury” to any attack it sustained.

“I believe our enemies know that,” he said. “The only good terrorist is a dead terrorist, and if and when America is attacked, it is our job to make as many that way as we possibly can.”