American weed is going global. Europe is not ready.

The 20th century was defined by American brands — McDonald’s and Coca-Cola, Microsoft and Starbucks — going global. In the 21st century, it’s artificial intelligence companies that are preparing to cannibalize the world economy. But the race to go global is on for another product: marijuana.

In America it has been a bumpy ride. The country long tried to effectively wipe weed off the face of the earth. But over the past decade or so, the pendulum swung: 24 states legalized recreational cannabis, and 41 states have legal medical markets. For a few years, venture capitalists poured their dollars into every hip-sounding weed company they could find, giving rise to the so-called green rush — a cannabis industry across the United States and Canada worth $30 billion at its peak.

But things were never steady. A patchwork of state laws, high taxes and overspeculation led to a cycle of boom and bust. Companies told their financial backers that federal legislation favoring the industry was imminent, but when that failed to materialize, investors pulled their cash. Profits stalled and stock prices collapsed. To many, it looked as though the cannabis industry would remain stuck in purgatory.

Then, at the end of last year, an unlikely savior arrived: President Trump. His executive order in December to reclassify cannabis promised to take the drug out of the category that includes heroin and place it alongside prescribed pain medications like codeine. It would also, importantly, spare companies from the heavy taxes that were strangling profits. The industry perked back up. Now North American cannabis companies are taking their wares overseas. And Europe, the first stop on their campaign of global conquest, is not ready.