WASHINGTON — Larry Klayman knew how to pick a legal fight long before Monday, when he took the first round in a judicial crusade on behalf of the little guy against big-government snooping. But not always a winning fight.

In the 1990s, he filed numerous lawsuits against President Bill Clinton and his administration, alleging a litany of personal and professional transgressions. Mr. Klayman later nettled Vice President Dick Cheney over his secret energy policy meetings and claimed that members of George W. Bush’s administration might have known in advance of the 2001 anthrax attacks in Washington.

More recently, Mr. Klayman, who has been called “Litigious Larry,” sued OPEC, accusing oil-rich nations of price fixing and of trying to “bring Western economies to their knees.” And he sued Facebook and its founder for $1 billion when, he said, it was too slow to take down a web page that threatened Jews with death.

Many of his lawsuits have fallen far short of the success bombastically predicted by Mr. Klayman. But on Monday, a federal judge agreed with his contention that the National Security Agency had exceeded its constitutional authority by systematically gathering the telephone records of Americans.