"Some years back I telephoned the DC office of one of my senators for help in identifying Members of Congress who hold dual citizenship. After a long pause, the response was unequivocal: “You are not entitled to that information!”
https://www.foreignpolicyjournal.com/2018/12/10/dual-citizens-in-congress-we-need-to-know/
Dual Citizens in Congress? We Need to Know
It’s important for citizens to know if their representatives have dual citizenship because both real and apparent conflicts of interest erode public trust.
https://www.foreignpolicyjournal.com/2018/12/10/dual-citizens-in-congress-we-need-to-know/