Finally, a breeze of sanity.

After 54 futile years of hard-line hostility, the United States will begin normalizing diplomatic ties with Cuba.

This unexpected outbreak of common sense and humanity was initiated by none other than Pope Francis, who privately reached out to President Barack Obama and Cuban President Raul Castro. He even let the negotiators use space in the Vatican.

As soon as the agreement was announced last week by Obama and Castro, the pontiff sent “warm congratulations for the historic decision.”

Politicians who are riled by the new diplomacy with Cuba wouldn’t dare trash the pope. It’s much safer to trash Obama, who at this point shouldn’t care what Sens. Marco Rubio or Ted Cruz has to say.

The key to the breakthrough was the return of ailing American contractor Alan Gross, who’d been imprisoned for five years. Cuba agreed to free Gross, 53 political prisoners and an agent for U.S. intelligence who’d been locked up for more than two decades.

In exchange, the United States released three Cuban nationals who had been convicted of spying here in 2001. Those on Capitol Hill who are criticizing the swap need to brush up on their math – Cuba freed a total of 55 prisoners and our government freed only three. How is that a bad deal?

More important, it opens the door to ending a festering standoff that has punished Cuban families on both sides of the Florida Straits, while diminishing U.S. influence in the Caribbean and the Americas.

Obama has humanely loosened travel rules for family visits to Cuba and increased fourfold the amount of money that Cuban Americans can send to relatives on the island.

In addition, the U.S. Embassy officially will reopen in Havana, and the two nations will begin cooperating more closely on efforts to curb drug smuggling, human trafficking and environmental destruction.

Cruz, Rubio, Jeb Bush and other presidential hopefuls would look like right-wing dinosaurs if they promise a new, harsher crackdown on Cuba. A solid majority of Americans favor open travel and free trade with the island. So do most Cuban Americans, according to a recent poll by Florida International University.

Other strong supporters of normalizing relations can be found throughout the U.S. corporate world, and they throw big money around at election time: General Motors, Caterpillar, the agribusiness mega-giant Cargill and furniture maker Ethan Allen Interiors, to name a few.

It’s astounding to hear people still trying to defend the U.S. strategy of isolating Cuba, which stands out as one of the worst foreign-policy backfires in diplomatic history. The trade embargo has only served to fortify the regime it was meant to topple, providing a desperately needed scapegoat first to Fidel and then Raul.

Every economic crisis that rocked Cuba has been pinned on the United States, deflecting blame from the ruinous fiscal policies of the Castro government.

Yet, as Miami’s exile community knows, the U.S. embargo has made life harder for the Cuban people, who at times are unable to obtain medicines and even such basics as bread and soap.

Despite the progress made last week, the embargo remains in place to punish everybody but the Castro brothers, who haven’t missed a meal since the revolution. Only an act of Congress can rescind the ban on trade and regular tourism, and the new Republican majority is unlikely to act.

That’s a true shame. The Cuban embargo isn’t just a fossilized flop; it’s indefensibly hypocritical.

America trades avidly with scores of countries that have lousy records on human rights.

China still detains thousands of political prisoners, but it’s a thriving market for U.S. companies such as Walmart, which has opened hundreds of stores there. Jeb Bush himself has a private-equity fund that raises money in China.

And remember a place called Vietnam? That’s where we lost a big nasty war, and more than 58,000 American lives.

Like Havana, Hanoi still maintains a socialist government, yet there’s no trade embargo. U.S. firms do billions of dollars in business there. Forty-two percent of all Nike shoes have a tag saying “Made in Vietnam.”

Half a century after the Cuban trade embargo was put in place, the folly of it is so obvious that Obama’s move to restore relations caused no uproar outside of South Florida and Capitol Hill.

Even in Little Havana, opinions were sharply and passionately divided.

Meanwhile, in the other Havana, the very people that the embargo was supposed to liberate poured into the streets to celebrate the prospect of its demise.

That says it all.