Richard Bruce Cheney had a wealth of political experience -- as a White House official, a congressman, a Cabinet official -- before becoming what analysts say is the most influential vice president ever.
And he has done that despite staying in the background for most of President Bush's first term, rarely seen or heard from in public until the 2004 presidential campaign was in full swing.
"His power is unparalleled in the history of the republic, frankly, for that position," John Hulsman, a research fellow at The Heritage Foundation, a conservative Washington-based think tank, told ABC News' "Nightline."
"Everybody knows that the vice president is going to fundamentally affect the foreign policy of the country," Hulsman added. When the vice president's office calls "you better get down there and you better wipe your hands on the side of your jacket on the way in the door."
But before becoming Bush's vice president, Cheney may have been most familiar to the public as defense secretary under the former President Bush. In that post, he earned widespread praise for his handling of the Gulf War in 1991.
Popular for Gulf Role
His most important test came after the Iraqi invasion and occupation of Kuwait in August 1990. Cheney oversaw the deployment of forces in the Persian Gulf before and during the war against Iraq that broke out in January 1991.
Cheney's management of the operation made him a popular figure -- if not as well-known as Colin Powell, the then-head of the Joint Chiefs of Staff.
As defense secretary, Cheney also took an active role in shaping U.S. national security policy, along with the elder President Bush and Secretary of State James Baker, in accordance with Cheney's stated policy: "Arms for America's friends and arms control for its potential foes."
Political, Business Experience
But Cheney is more than a defense expert. He has a background as a business executive and an unusually diverse political background, having seen the White House from the inside as former President Ford's chief of staff at the young age of 34 -- and having served in Congress for a decade as the sole representative from Wyoming.
Prior to being tapped as vice president, Cheney worked in the private sector, serving as chief executive officer of Halliburton Co., a Texas-based Fortune 500 energy services company specializing in the development of oil and gas production around the world.
Cheney's stint as secretary of defense came despite what some said was a lack of military experience.
During the Vietnam War, when Cheney was draft-eligible, he received deferments as a student, and then as a registrant with a child.
"I had other priorities in the '60s than military service," Cheney told a reporter in 1989, according to The Washington Post. However, in his Senate confirmation hearing, Cheney said he "would have been obviously happy to serve had I been called."
Born in Nebraska in 1941, Cheney grew up in Casper, Wyo., then headed East to attend the Bush family alma mater, Yale University. But he dropped out during his sophomore year, and eventually earned a political science degree at the University of Wyoming in 1965.
After winning a postgraduate fellowship that took him to Washington, Cheney took a job in the Nixon administration as a special assistant to Donald Rumsfeld, who was director of the Office of Economic Opportunity, then White House counsel.
In August 1974, after President Nixon resigned from office, Rumsfeld was called to join the White House staff as an assistant to Ford, and Cheney moved along with Rumsfeld. Hard-working, loyal and good-natured, Cheney made a good impression and became Ford's chief of staff from 1975 to 1977.
After Ford's loss to Jimmy Carter in 1976, Cheney decided to run for office himself, winning Wyoming's House seat in 1978, despite suffering the first of four heart attacks.
Cheney quickly rose in the Republican ranks, eventually becoming House minority whip.
After suffering two more heart attacks in the 1980s, Cheney had quadruple bypass surgery in 1988. He suffered a minor heart attack in November 2000, and has a device known as an ICD implanted to regulate his heartbeat. The so-called "pacemaker plus" monitors the heart rate and stimulates the heart with electricity to correct an irregular rhythm.
He also takes medication to lower his cholesterol, and recently said he has changed to a healthier diet and is exercising.
A Powerful Vice President
Cheney's influence and his links to the energy sector have often put Bush's administration under public scrutiny.
Following the collapse of Enron, there were calls to get Cheney to testify about his contacts with the energy giant. But Cheney has refused to testify.
The Iraq war has also exacerbated the pressures on the vice president. His critics maintain that Halliburton has unfairly won lucrative contracts in Iraq. Halliburton was also the focus of a Securities and Exchange Commission investigation into accounting practices begun when Cheney was head of the company.
Cheney is married to Lynne Vincent, best known for serving two terms as chairwoman of the National Endowment for the Humanities. They have two daughters, Elizabeth and Mary.