President Donald J. Trump put Europe on notice Monday night. Speaking to a packed midterm rally in Park City, Kansas, the President said America still stands with its old allies, but not forever. “We stand with Europe despite its flaws, its weaknesses,” he said. “But if they don’t soon find their way, and they have to find their way, we will have no choice but to leave. We will have no choice. It’s a very serious situation.”

Trump said he saw the trouble coming long ago. “I could see it coming 10 years ago,” he said. He told the crowd that France, “a once great nation,” is “being conquered, looted, and burned to the ground by migrants, jihadists, and communists who hate Christianity,” and that Europe’s leaders have “surrendered their country to vandals who could have never built it themselves.” He repeated what he told French President Emmanuel Macron years ago: close your border or you will lose France.

The President also revealed a test he gave the allies. “When we asked for help in Iran, help which we didn’t need, we didn’t need, but I wanted to, I was testing, I wanted to find out, listen, would you help? Because we spend so much money in NATO,” he said. “They weren’t there to help.” He added: “We spend hundreds of billions of dollars a year on NATO protecting them. But when we said, would you like to help? No thank you.”

Trump tied the warning straight to the midterms. “When you see burning steeples and raging fires in France, just remember that is what the radical Democrats want to do to America,” he said. “They’re not going to come close.” Of Europe’s collapse, he promised: “We’re not letting it happen here.”

The crowd overflowed the venue. Trump said about 5,000 people were standing outside watching on a jumbotron. “We love you out there too,” he told them. America First means America’s friends carry their share, and America’s borders stay closed.