Ensign, John E. (John Eric), 1958-

John Eric Ensign (born March 25, 1958) is an American veterinarian and former politician from Las Vegas, Nevada. A member of the Republican Party, Ensign was a Congressman and United States Senator from Nevada; he served in the latter seat from January 2001 until May 2011, when he resigned amid a Senate Ethics Committee investigation into his attempts to hide an extramarital affair. Following his resignation from the Senate, Ensign returned to Nevada and resumed his career as a veterinarian.

Born in Roseville, California, he spent his childhood in northern Nevada, later moving to Las Vegas where he graduated from E.W. Clark High School. After attending the University of Nevada, Las Vegas before earning a B.S. from Oregon State University and D.V.M. from Colorado State University. Upon graduating, he completed a one-year internship at the West Los Angeles Veterinary Medical Group before opening the first 24-hour animal hospital in Las Vegas. He owned two animal hospitals before entering politics.

In 1994, Ensign was elected to the U.S. House of Representatives from Nevada's 1st congressional district, based in Las Vegas. He was re-elected in 1996. In 1998, he ran for the U.S. Senate, challenging Democratic incumbent Harry Reid; Ensign lost by less than 500 votes. In 2000, Ensign ran for the open U.S. Senate seat being vacated by Democrat Richard Bryan, winning by a 15-point margin. In 2006, Ensign was re-elected. During his time in Congress, Ensign was considered one of the Humane Society's biggest allies. He was a lead sponsor of the Animal Fighting Prohibition Enforcement Act, which makes it a felony to transport animals across state lines for the purpose of fighting. Ensign opposed President Barack Obama's health reform legislation; he voted against the Patient Protection and Affordable Care Act in December 2009 and he voted against the Health Care and Education Reconciliation Act of 2010. He served as chair of the National Republican Senatorial Committee from 2007 to 2008 and chair of the Republican Policy Committee in 2009. Amid a Senate Ethics Committee investigation into his attempts to hide an extramarital affair, Ensign resigned from the Senate in May 2011.

In 2013, Ensign opened Boca Park Animal Hospital in Las Vegas.