Two items from Berger's Wikipedia biography:
Opposed to the Vietnam War, Berger began working for Senator George McGovern's presidential campaign in 1972. While there, he met Bill Clinton, forming a friendship that would last for decades. Berger later urged Clinton to run for president.[2]
"Sandy Berger," Nancy Pelosi said in 1997 prior to becoming Speaker of the House, "was the point person at... Hogan & Hartson... for the trade office of the Chinese government. He was a lawyer-lobbyist."[4]