Following the 1964 National Service Act, legislated in response to the Indonesia–Malaysia confrontation, 20-year-old Australian men were subject to military service based on a birthday lottery. In April 1965, Prime Minister Sir Robert Menzies sent a battalion of Army regulars to Vietnam, beginning an overseas involvement in that country which lasted for seven years and provoked deeply divisive debate back home. In early 1966, Menzies retired and Harold Holt became Prime Minister. In March 1966, Holt announced troop increases bringing the total commitment to 4,500 men in Vietnam, a tripling of effort. Significantly, conscripts could now be sent into combat. Protests broke out, including a draft-card burning demonstration outside of Holt's home. In late June 1966 with President Lyndon B. Johnson listening, Holt spoke in Washington, D.C. in support of American policy. In his speech he closed by saying that Australia was a "staunch friend" of America, willing to go "all the way with LBJ". This statement was widely criticized in Australia. Marxist writer and draft-card burner Andy Blunden said in July that, "by following America into Vietnam, Holt's Australia is playing the role of Mussolini's Italy." In December the government bolstered the Vietnam presence with 1,700 more troops.