The European leaders would have have no say in it. If the software from Seattle is designed to covertly exfiltrate information, they won't even know it. Even if they review the individual code changes, it can be an obfuscated attack similar to XZ where the code itself is clean, but not so much for the network fabric firmware binary test data.
That's why I used the "somehow". But abiding your logic nothing is ever secured, which is ultimately true, but it could be illegal so detergent here is not the impossibility it self but potentional harsh punishment for breaking the law.