For a few months in 1966, the budding romance between film star George Hamilton and Lynda Bird Johnson, daughter of the 36th president, was the talk of Washington.

Gossip columnists followed their every move as Hamilton squired her around town. The couple vacationed in Acapulco and made camera-ready appearances at the Sugar Bowl, Mardi Gras, and the Oscars. The actor spent Easter at the LBJ ranch in Texas and even attended the Washington wedding of Lynda's sister Luci.

President Johnson made no secret of his suspicions about the handsome, patent-leather playboy, perhaps best known now for his perpetual tan, blinding smile, and roles on TV shows ranging from Columbo to Dynasty to Dancing With the Stars.

But a previously confidential FBI file - which a Philadelphia judge last week outlined in an opinion and ordered to be released - shows for the first time how far Johnson went to protect his daughter and his presidency.