Germany was very much in line with the Iraq invasion. We didn't provide boots on the ground, but US army bases in Germany were used extensively for logistics and the German army was aiding in the defense of these bases as well as in surveillance operations. And Merkel, who became chancelor in 2005 was in favor of Germany also commiting troops to the Iraq invasion in 2003.

The Iraq invasion is the same in terms of international law like the russian invasion of Ukraine. An illegal foreign invasion. But instead of calling the US out on it, demanding sanctions or at least forbid and enforce no war efforts going through army bases in Germany, the government decided to let the US reign freely and even protect their back, while they are busy invading.