And then did everything he could to allow the USA the more efficient destruction of Iraq like protecting US bases (while the GIs went head-banging to Iraq) and giving B-52s passing rights. By normal standards, Germany did participate in the Iraq war.There was a re-election in Germany in 2002 and Gerhard Schröder got a good part of votes because he was categorically against a german participation in your Iraq adventure. And why would he want to join you given the more than shaky "evidences"?
Most Western strategists agreed on the general necessity to "do something in Middle East". Most opponents did not dispute the removal of Sadam Hussein, but rather the risks connected to it (and were ultimately right). That this kind of war was nothing compatible to the general public is another thing.
Costa Rica joint the Coallition? They don't even have an army.