ALBANY — A quarter of a century after they helped to enact the Rockefeller drug laws, a group of former government leaders is proposing a new plan to reform the strict mandatory sentencing statutes they now view as an expensive failure.

The plan, which former State Senator John R. Dunne said he will soon begin circulating among lawmakers, would give trial judges much greater discretion over sentencing and plea bargaining for nonviolent drug offenders.