The adjective “constitutional” is never capitalized....

Should constitutional capitalized?

You are right. The “Constitution,” referring to the US Constitution, is capitalized. The adjective “constitutional” is never capitalized.

Does Constitution need to be capitalized UK?

When it comes to the government, capitalization rules may not really apply. While normally the word constitution would be in lowercase, when referring to the government's document, it is capitalized. In such a scenario, it is treated as a proper noun and thus capitalization has to apply.