I think it’s appropriate a U.S. senator,Congressman or house of representative representing The American People should only be an American Citizen. One cannot serve two masters, let there be no conflict of interest.
"I hereby declare, on oath, that I absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty, of whom or which I have heretofore been a subject or citizen; that I will support and defend the Constitution and laws of the United States of America against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same"