Thornberry is a lifelong resident of Clarendon, the seat of Donley County, some 60 miles (97 km) east of Amarillo. His family has operated a ranch in the area since 1881. He received his B.A. in history from Texas Tech University in Lubbock. He obtained his Juris Doctor from the University of Texas Law School. He served as a staffer to two other Texas Republican congressmen, Tom Loeffler and Larry Combest, and as deputy Secretary of State for Legislative Affairs before joining his brothers on the family ranch.

Thornberry defeated Democratic Congressman Bill Sarpalius in the 1994 general election, a heavily Republican year nationwide. He polled 79,416 votes (55.41 percent) to Sarpalius' 63,923 ballots (44.18 percent). Two years earlier in a much higher turnout election, Sarpalius had polled nearly double the votes that he received in 1994. The 13th has always been a somewhat conservative district, but Thornberry's victory is still regarded as an upset.

Since his initial election, Thornberry has consolidated his hold on the district and routinely wins by large majorities in an area that was historically Democratic as recently as the 1970s.

Thornberry is only the third Republican to represent the district since Reconstruction. The previous GOP representatives were Robert D. "Bob" Price of Pampa (1967–1975) and Beau Boulter of Amarillo (1985–1989).

In the 2006 election, Thornberry defeated former Intelligence Officer and Professor Roger Waun.

External links

• U.S. Representative Mac Thornberry official House site
• Federal Election Commission — Mac Thornberry campaign finance reports and data
• On the Issues — Mac Thornberry issue positions and quotes
• OpenSecrets.org — Mac Thornberry campaign contributions
• Project Vote Smart — Representative William M. 'Mac' Thornberry (TX) profile
• SourceWatch Congresspedia — Mac Thornberry profile
• Washington Post — Congress Votes Database: Mac Thornberry voting record