For corporate America's top lobbyists, trying to curb a powerful antibribery law known as the Foreign Corrupt Practices Act has risen to the top of the agenda, sparking a widespread debate about how the legislation is enforced.

In the past five years, a remarkable run of enforcement of the U.S. law has led to about $4 billion in penalties against corporations. The law prohibits companies from paying bribes to foreign officials to win business. A violation can result in criminal prosecution.

Congress...