Which bit of the constitution does this violate? Not american (Uk) actually interested in why.

I'm reading this in the "spirit" of the law based on what i know and my interpretation of whats been linked to me.

My understanding is you have laws in effect to stop people profiting or being unduly influenced by money while in office (lets just pretend lobbying and post office jobs isn't a thing for simplicity, if its important to your argument thats fine). From what i've seen Trump isn't earning more from his presidency that he was before.

The biggest problem i see is we dont really know exactly what he's earning (tax returns?). That seems more like an easily fixable issue with your financial disclosure laws for presidential earnings/candidates?