Final answer:
Don't Ask Don't Tell (DADT) was a policy prohibiting military members from inquiring about service members' sexual orientation and discharging those who were openly homosexual. Enacted in 1993 by President Bill Clinton, it was repealed in 2011 via a federal court ruling.
Step-by-step explanation:
Don't Ask Don't Tell (DADT) was the Department of Defense policy concerning the service of homosexuals in the U.S. military. Under this policy, military personnel were not permitted to inquire about a service member's sexual orientation, effectively barring openly gay, lesbian, or bisexual individuals from serving.
Those who did not disclose their sexual orientation were allowed to serve, however, if a service member openly acknowledged being homosexual, they would be subject to dismissal from the military. This policy was enacted during President Bill Clinton's administration in December of 1993 and lasted until it was repealed following a federal court ruling in July 2011 which prohibited its enforcement.