In a move with significant implications for the U.S. housing market, Florida Republican Sen. Marco Rubio is seeking to take a Treasury Department crackdown on dirty money in luxury real estate and expand it from a few high-priced enclaves to the entire nation.

Rubio says his proposal is an attempt to root out criminals who use illicit funds and anonymous shell companies to buy homes — a form of money laundering that hides the cash’s tainted origin from law enforcement and banks. The widespread practice enables terrorism, sex trafficking, corruption, and drug dealing by providing an outlet for dirty cash, according to transparency advocates.