War against Iran is a "catastrophic mistake" that violates international law, Germany's president said on Tuesday in an unusually open rebuke of US President Donald Trump's foreign policy.
This marked a severance of German ties with its largest post-war ally, he added.
In a harsh verbal attack, Frank-Walter Steinmeier, whose largely ceremonial role allows him to speak more freely than politicians, took a much more critical line than Chancellor Friedrich Merz, who has sidestepped questions about the legality of the war.
"Our foreign policy does not become more convincing just because we do not call a violation of international law a violation of international law," Steinmeier, a former foreign minister from the center-left Social Democratic Party, said in a speech at the Foreign Ministry.
"We need to address this in relation to the war in Iran. Because, in my opinion, this war is contrary to international law," he said, adding that there was no doubt that the justification of the imminent nature of an attack on American targets did not hold water.
Calling the war unnecessary and a "catastrophic political mistake," Steinmeier said Trump's second term marked a disruption in German foreign relations as profound as Russia's invasion of Ukraine.
"Just as I believe that there will be no return to relations with Russia as they were before February 24, 2022, I also believe that there will be no return to transatlantic relations as they were before January 20, 2025," Steinmeier said.
Germany needed to apply the lessons it learned by freeing itself from "overdependence" on Russia and apply them to the US, especially in defense and technology, which translate into power, he said.
Germany has stressed the importance of creating alternatives to US-dominated technology, as concerns grow about US access.
China returned to being Germany's top trading partner in the first eight months of 2025, surpassing the US, as higher tariffs hit German exports. Trade between the US and Germany reached more than $190 billion during that period.
