Leadership. That’s what we lacked for eight years. In the early hours of Friday morning in Syria — late Thursday evening here — our military, acting on the order of our commander-in-chief, avenged the slaughtered innocents in Syria and sent a clear message that we will not tolerate the use of chemical weapons. Well done!

Waves of more than 50 cruise missiles, launched from US warships, struck the Syrian air base from which Tuesday’s chemical-weapons attack on a Syrian town had been launched. The strikes targeted aircraft, fuel supplies, arms stocks and runways. This was exactly the right approach: enough to hurt. President Trump just put an end to the Obama era of vacillation and cowardice.

Trump also ignored Russia’s shameless prevarications. We did warn the Russians to evacuate any of their personnel who were on the base — which may also have alerted the Syrians — but the point was made: Slaughter the innocent and there’s one country left in the world that won’t allow it.

Incontestably, our president became . . . presidential. He passed his first pressing foreign-policy test with dispatch and guts.

To know the full results of our attack, we’ll have to wait for imagery, daylight and bomb-damage assessment. No attack goes perfectly. But Trump just sent a vital message — to the butcher Bashar al-Assad, and also to North Korea’s Kim Jong-un and other rogue leaders:

The United States is back. There are, indeed, red lines. And the enemies of humanity cross those lines at their peril.

Nor was the lesson lost on President Xi Jinping of China, who, with perfect timing, is our president’s guest at Mar-a-Largo.

The coming days will see no end of partisan second-guessing, hand-wringing and, yes, actual repercussions. But President Trump did the right thing. Relying on the strong backbones of Secretary of Defense Jim Mattis, National Security Advisor H.R. McMaster and, not least, our men and women in uniform, the president knocked it out of the park on his first time at bat in the foreign-policy big leagues.

As I write these lines, I’m unabashedly proud to be an American. Republican, Democrat or independent, you should be, too. Once again, we stood on the side of justice and humanity.

It’s been too damned long, but we’re back.