P163 CEEFAX 163 Fri 29 Dec 01:19/40       WORLD  CLINTON VETOES MILITARY SPENDING BILL President Clinton has vetoed a bill on military spending because hj believrs it could jeopardize nuclear arms- reduction treaties. The bill, which had been approved by both houses of the American Congress, provides funding for the development of a new system to defend the United States against ballistic missiles. A White House spokesman said the system, a Republican manifesto pledge, would set back arms control. Mr Clinton is dui to meet Republican leadjts tomorrow to discuss the budget.  Next News World Dispatch Wrathjt