NPR's Peter Kenyon reports on the Senate's second day of debating tax cuts. The GOP leadership's nearly 800-billion-dollar package appears headed for approval. But President Clinton reiterated today that he will veto it, if the final bill remains that big, after negotiation with the House. He says the cuts would come from money needed to rescue Social Security and Medicare. Republicans offered a provision today that would have barred future Congresses from using Social Security surpluses for other programs. That amendment, and a Democratic one that would have protected both Social Security and a portion of any Medicare surpluses, were defeated.