President Trump is inciting a trade war, undermining NATO and painting Europe as a foe. It’s no wonder, then, that the European Union is looking elsewhere for friends.

On Tuesday in Tokyo, it signed its largest trade deal ever, a pact with Japan that will slash customs duties on products like European wine and cheese, while gradually reducing tariffs on cars. The agreement will cover a quarter of the global economy — by some measures the largest free-trade area in the world — and is the latest in a string of efforts either concluded or in the works with countries like Australia, Vietnam and even China.

The deal with Japan, and the others being negotiated, point to a more assertive Europe, one that is looking past the frosty ties with the United States, and even the coming withdrawal of Britain from the bloc. In recent months, European Union leaders have voiced ever more confident support for free trade, refusing to back down in the face of the threat of tariffs from Washington and instead aggressively courting new relationships.

But no matter how many barriers to international commerce the European Union manages to tear down, its leaders will not change one economic fact of life: The United States remains the Continent’s largest trading partner. There is no escaping the damage from Mr. Trump’s campaign against imports like cars and steel.