The New York Times reports that Judge Richard J. Leon of United States District Court for the District of Columbia on Nov. 9 partly blocked the National Security Agency’s collection of Americans’ domestic phone records, weeks before the agency was scheduled to shut it down and replace it. Leon said the program was most likely unconstitutional in a 43-page ruling. “With the government’s authority to operate the bulk telephony metadata program quickly coming to an end, this case is perhaps the last chapter in the judiciary’s evaluation of this particular program’s compatibility with the Constitution,” Leon wrote. “It will not, however, be the last chapter in the ongoing struggle to balance privacy rights and national security interests under our Constitution in an age of evolving technological wizardry.” Judge Leon stopped the N.S.A. from collecting phone records for a lawyer in California and his law firm, a customer of Verizon. The Justice Department previously said that blocking just one person’s records might require shutting down the entire program. Reuters reported that on the same day the N.S.A. sent a memo to Congress saying it had begun testing a replacement system.