I'm not sure where to post this, as it's a British action, but it relates to US government. Are trade deals a federal thing governed by the national government, or is it actionable by individual states? Is it possible to bypass the executive (President)? Presumably the President has to sign it off at some point, but does it have to go through the Houses of Congress as well?

I'm asking this because, according to one of our papers, the UK government is planning to bypass Biden by signing trade deals with individual US states.