"Don't Ask, Don't Tell" (DADT) was the official US military policy towards homosexual service members from December 1993 to September 20, 2011, which mandated that "closeted" homosexual service members were allowed to serve in the military while homosexual or bisexual persons who revealed their sexual orientation were subject to discharge upon discovery. DADT originated in 1993 following a political conflict between President Bill Clinton and the US Congress. Clinton had advocated to end the ban on homosexuals in the military during his 1992 presidential campaign, but Congress included text in the National Defense Authorization Act for Fiscal Year 1994 which effectively prohibited all gay, lesbian, and bisexual persons from serving in uniform. The Clinton administration responded by issuing Defense Directive 1304.26 on December 21, 1993. The order directed that military applicants could not be asked about their sexual orientation, although a similar internal, interim policy had been in place since January 1993. These two legal actions created the general policy of DADT. DADT has been the source of deep controversy in the military and social arenas of American politics since it was adopted. According to its supporters, DADT is necessary to protect unit cohesion, military readiness, combat effectiveness and recruiting and retention in the armed services. Among these supporters is retired US Marine Corps General John Sheehan, who testified before the US Senate Armed Services Committee that the inclusion of homosexual soldiers in the Dutch military rendered its armed forces weaker and less effective and directly contributed to the 1995 Srebrenica massacre.