Enron's initial efforts in 1996 to persuade Congress to change the law were thwarted by opposition from a powerful trade group and some federal regulators. The company responded by hiring the former boss of a leading staff official at the Securities and Exchange Commission to represent it in negotiations with the agency. In an unheralded five-paragraph order in March 1997, the S.E.C. official, Barry P. Barbash, gave Enron's foreign operations a broad exemption from the law -- the Investment Company Act of 1940.