The Obama administration on Monday made public a previously classified letter from 2002 about the Bush administration’s secret program that allowed the National Security Agency to eavesdrop on Americans’ international communications without court orders. The letter, written by John Yoo, then a top lawyer in the Justice Department’s Office of Legal Counsel, adds to the historical record of the surveillance and bulk data collection program known as Stellarwind. It explained to Colleen Kollar-Kotelly, then the newly installed chief judge of the Foreign Intelligence Surveillance Court, why the Justice Department had blessed the program as lawful even though, as Mr. Yoo acknowledged, that it probably clashed with wiretapping laws.