Claim: John McCain adheres to conservative principles.

John Sidney McCain III -LRB- born August 29 , 1936 -RRB- is an American politician who currently serves as the senior United States Senator from Arizona . He was the Republican nominee for the 2008 U.S. presidential election .   McCain followed his father and grandfather , both four-star admirals , into the United States Navy , graduating from the U.S. Naval Academy in 1958 . He became a naval aviator , flying ground-attack aircraft from aircraft carriers . During the Vietnam War , he was almost killed in the 1967 USS Forrestal fire . In October 1967 , while on a bombing mission over Hanoi , he was shot down , seriously injured , and captured by the North Vietnamese . He was a prisoner of war until 1973 . McCain experienced episodes of torture , and refused an out-of-sequence early repatriation offer . His war wounds have left him with lifelong physical limitations .   He retired from the Navy as a captain in 1981 and moved to Arizona , where he entered politics . Elected to the U.S. House of Representatives in 1982 , McCain served two terms . He was first elected to the U.S. Senate in 1986 , winning re-election easily five times , most recently in 2016 . While generally adhering to conservative principles , McCain at times has had a media reputation as a `` maverick '' for his willingness to disagree with his party on certain issues . After being investigated and largely exonerated in a political influence scandal of the 1980s as a member of the Keating Five , he made campaign finance reform one of his signature concerns , eventually gaining passage of the McCain -- Feingold Act in 2002 . He is also known for his work in the 1990s to restore diplomatic relations with Vietnam , and for his belief that the Iraq War should have been fought to a successful conclusion . McCain has chaired the Senate Commerce Committee , opposed spending that he considered to be pork barrel , and played a key role in alleviating a crisis over judicial nominations with the bi-partisan group known as the Gang of 14 .   McCain ran for the Republican nomination in 2000 but lost a heated primary season contest to George W. Bush of Texas . He secured the nomination in 2008 after coming back from early reversals , but was defeated by Democratic candidate Barack Obama in the general election , losing by a 365 -- 173 electoral college margin and by 53 -- 46 % in the popular vote . He subsequently adopted more orthodox conservative stances and attitudes and largely opposed actions of the Obama administration , especially in regard to foreign policy matters . By 2013 , however , he had become a key figure in the Senate for negotiating deals on certain issues in an otherwise partisan environment . In 2015 , McCain became chairman of the Senate Armed Services Committee .