Secretary of State Hillary Clinton came to the defense of the Foreign Corrupt Practices Act Thursday night, saying the Obama Administration is "unequivocally opposed to weakening" the anti-bribery law.

Clinton's remarks come amid a full-press lobbying effort by the U.S. Chamber of Commerce to amend the 1977 law, which prohibits bribes to foreign officials to win business. The Chamber argues the law is vague, over-broad and detrimental to U.S. businesses.

Clinton...