A LEADING crusader for Hongkong in the American Congress, Mr John Porter, has made a new push for a Radio Free Asia aimed mainly at promoting democracy in China as debate on the controversial issue heated up afresh. Testifying at a congressional committee, Mr Porter slammed critics who argued against pumping money into a new American-funded democracy radio run independently rather than by a United States government agency. Charging that a government-run Radio Free Asia would encounter censorship by the State Department, Mr Porter said a democracy radio run by an independent agency would provide ''a firewall of protection'' against official meddling. Virtually all participants in the ongoing debate agree that a Radio Free Asia is needed but they are sharply divided on whether it should be run by an independent body like the Board of International Broadcasting (BIB) or be part of the Voice of America (VOA) which is run by the US Information Agency (USIA), a government body. President Mr Bill Clinton who backed a Radio Free Asia during the election campaign has recently proposed that it come under USIA as part of an overall plan that would scrap the BIB. But Mr Porter told the congressional committee that if the Asia project came under VOA it would ''kill free radio''. Mr Porter defended the US$30 million (about HK$234 million) start-up cost for the project, saying that while this amount would buy only one F-16 warplane, it was enough to ''make an impact on all the closed societies of Asia'' including China, Vietnam, North Korea, Laos, Cambodia, and Burma. Meanwhile, the Reuter news agency reported that a bill to establish the Radio Free Asia has been introduced in the US Senate.