 He authored and co-authored landmark pieces of legislation during the 11th Congress which includes RA 8972 –"An Act to Facilitate the Acquisition of Right-of-Way, Site or Location for National Government Infrastructure Projects and for Other Purposes"; RA 8975 – An act to Ensure the Expeditious Implementation and Completion of Government Infrastructure Projects by prohibiting Lower Courts from Issuing a Temporary Restraining Orders, Preliminary Injunctions or Preliminary Mandatory Injunctions", RA 8799 – The Securities Regulation Code; RA 8749 "An Act providing for a Comprehensive Air Pollution Control Policy, and For Other Purposes (Clean Air Act); RA 8792 – "An Act Providing for and Electronic Commerce Law and for Other Purposes (E-Commerce Law) RA 9139 – "Administrative Naturalization Law of 2000"; RA 9136 – Electronic Power Industry Reform Act of 2201" and RA 9006 – The Fair Elections Act.He was also responsible for Republic Act 9048 aimed at correcting clerical and typographical errors in an entry in personal legal documents as the city or municipality civil register level.During the impeachment trial of former President Estrada, he was one of the ten Senator-Judges who voted for the opening of the second envelope, an event that triggered People Power II, which eventually led to the ousting of the former president.