Leaders of close American allies don’t typically slam the US president at home to win political points. But that’s just what happened on Thursday, when German Chancellor Angela Merkel implicitly, but unmistakably, ripped into President Donald Trump in a speech at the German parliament.

“Whoever believes that you can solve problems through isolation and protectionism is making a grave error,” Merkel said, a clear shot at Trump’s hostility to international trade and institutions like NATO. “The world has become less united. ... The discord is obvious and it would be dishonest to paper over the conflict.”

She had particular scorn for Trump’s withdrawal from the Paris climate agreement.

“We want to tackle this existential challenge and we can’t and we won’t wait until the last person on earth is convinced of the scientific basis for climate change,” she said.

One gets the strong impression that the phrase “last person” is not a rhetorical device, but rather a reference to a specific American president.

Part of this is clearly campaign rhetoric. Merkel is up for reelection; her leading opponent, Martin Schultz, has made attacking Trump a mainstay of his campaign rhetoric. The chancellor doesn’t want to be seen as soft on Trump — he’s wildly unpopular in Germany — so a little Trump bashing in a high-profile speech probably doesn’t hurt her chances.

But there’s a part of it that is a simple reflection of a depressing reality. European leaders have rightly concluded that a Trump-led United States can’t really be relied on in the way that the country has been in the past, for reasons that go well beyond general Republican hostility to doing anything about climate change.

Trump’s stance on NATO, arguably the most bedrock commitment in modern US foreign policy, has constantly shifted. First he says NATO is obsolete, then he says it isn’t; first he says he isn’t sure if he’d defend a NATO ally if attacked, then he says he would.

This is particularly worrying to Germany, which has maintained a relatively tiny military since World War II by outsourcing its defense to the United States. If Germany can’t trust that the US will continue to defend Europe’s borders, especially in the face of a resurgent Russia, then any sane German chancellor would have to start worrying.

Trump seems to wants a weak Europe. Leaders like Merkel have noticed.

But it isn’t simply that Trump is wavering on American support for Europe. He also appears to genuinely want to see a weaker and less unified Europe.

He loudly cheered Britain’s vote to exit the European Union. In France’s election this spring, he all-but-endorsed far-right candidate Marine Le Pen, who supported the idea of a French departure from the UN. French President Emmanuel Macron, who won the election, has since become the most vocally anti-Trump leader in the European Union.

Germany’s economy has benefitted greatly from the EU’s common market; having a US president not-so-subtly cheer efforts to undermine it in France and Britain has to look worrying to Berlin. And Trump has insulted Merkel personally as well, even failing to acknowledge her request for a handshake during a photoshoot.

Trump, in short, is upsetting the two core institutions — NATO and the EU — that Germany’s entire approach to the world depends on, and being rude to its leadership to boot. So of course Merkel is mad, and of course she sees the world as being “less united.” That’s what Trump appears to want.

Next week, Merkel will meet with Trump at the G20 summit, an annual confab for leaders of some of the world’s most significant economies. She said in her Bundestag speech that the talks there “will be very difficult.” She’s right.