The revelation that an ally of the National Security Agency spied on an American law firm’s communication with a foreign government will further expand the debate on Capitol Hill about the propriety of government surveillance.

The New York Times on Saturday said the Australian ally of the NSA eavesdropped on the communication of a law firm and its client, the Indonesian government. Sen. Patrick Leahy (D-Vt.), the judiciary committee chairman, intends to follow up on questions that the report raised, an aide said Tuesday.