In Pictures: Newt, now and then
In Pictures: Texas Gov. Rick Perry
In Pictures: Ron Paul: populist for president
Gallery: Babies in politics
Gallery: Notable women in US politics
In Pictures: Inside President Obama's White House
Taking a US tour in a patriotic campaign bus is a rite of passage for any serious presidential contender. Republican presidential candidate Texas Gov. Rick Perry and wife Anita head back to the campaign bus after a stop at D.C. Taylor Roofing in Cedar Rapids, Iowa, on Aug. 16. Charles Dharapak/AP
Republican presidential candidate Rep. Michele Bachmann of Minnesota waves from the steps of her campaign bus after being named the winner of the Iowa Republican Party's Straw Poll in Ames, Iowa, on Aug. 13. Charlie Neibergall/AP
Republican presidential candidate Herman Cain gets off his tour bus to greet supporters at the 2011 Ames Straw Poll held on the campus of Iowa State University in Ames, Iowa, on Aug. 13. Zuma Press/Newscom/File
President Obama steps off his bus as he visits Maquoketa High School in Maquoketa, Iowa, on Aug. 16, during his three-day economic bus tour. Mr. Obama was careful to say he was not campaigning for reelection. Carolyn Kaster/AP
The tour bus of Sarah Palin, former GOP vice presidential candidate and Alaska governor, is parked outside Independence National Historical Park Tuesday in Philadelphia on May 31. Ms. Palin emphatically denied that her tour had anything to do with running for president. Matt Rourke/AP/File
Sen. John McCain is greeted by a cheering crowd as he arrives in Springfield, Va., aboard his presidential campaign bus called the 'Straight Talk Express' on Nov. 1, 2008. Lee Love/Newscom/File
The tour bus carrying Democratic presidential candidate, former senator John Edwards, winds its way through Jefferson, Iowa on Aug. 13, 2007. Andy Nelson/Staff/File
Republican presidential hopeful and Massachusetts Gov. Mitt Romney exits his campaign bus as he arrives for a Caucus Countdown event at Potter's Mill in Bellevue, Iowa, on Dec. 31, 2007. Dennis Van Tine/Abacausa.com/Newscom/File
US Senator and Democratic presidential candidate Hillary Clinton (l.) walks with middleweight boxing champion Kelly Pavlik to show him her campaign bus after a rally at Austintown-Fitch High School in Austintown, Ohio, on March 2, 2008. Robyn Beck/AFP/Getty Images/Newscom/File
US President George W. Bush rides in the front of his campaign bus after speaking at the Waukesha County Exposition Center in Waukesha, Wisc., on July 14, 2004. Larry Downing/Reuters/File
Arkansas Gov. Bill Clinton and Sen. Al Gore's campaign tour bus is shown in Texas in 1992. The slogan on the side of the bus reads 'On the Road to Change America.' Newscom/File
Photos of the Day: Photos of the day 05/21
In Pictures: Sinkholes around the world
In Pictures: What happened to the green revolution in Iran?
In Pictures: Facing the devastation of the Oklahoma tornadoes
In Pictures: Sandy: Chronicle of an unrelenting storm
Photos of the Day: Photos of the day 05/20
In Pictures: Weather extremes 2013
In Pictures: The Israeli separation barrier: A West Bank wall
In Pictures: Derby Day devotees, Kenyan style
Weekend polling indicated that Ted Cruz, the Tea Party's choice for the U.S. Senate seat that's up for grabs in Tuesday's Texas runoff, is leading. However, his opponent, the GOP pick, Lieutenant Governor David Dewhurst still has a pretty good chance.
Voters began heading to the polls on Tuesday in Texas, where Tea Party movement favorite Ted Cruz is hoping to upset Lieutenant Governor David Dewhurst in a fiercely competitive Republican primary runoff for an open U.S. Senate seat.
/Photo-Galleries/Photos-of-the-Day/2013/Photos-of-the-day-05-21
/Photo-Galleries/In-Pictures/Sinkholes-around-the-world
/Photo-Galleries/In-Pictures/What-happened-to-the-green-revolution-in-Iran
/Photo-Galleries/In-Pictures/Facing-the-devastation-of-the-Oklahoma-tornadoes
/Photo-Galleries/In-Pictures/Sandy-Chronicle-of-an-unrelenting-storm
/Photo-Galleries/Photos-of-the-Day/2013/Photos-of-the-day-05-20
/Photo-Galleries/In-Pictures/Weather-extremes-2013
/Photo-Galleries/In-Pictures/A-West-Bank-wall
/Photo-Galleries/In-Pictures/Derby-Day-devotees-Kenyan-style
/Photo-Galleries/Photos-of-the-Day/2013/Photos-of-the-day-05-16
/Photo-Galleries/In-Pictures/Dazzle-like-Beckham
/Photo-Galleries/In-Pictures/Covert-commerce-smugglers-tunnels-at-the-Egypt-and-Gaza-border
/Photo-Galleries/Photos-of-the-Day/2013/Photos-of-the-day-05-15
/Photo-Galleries/In-Pictures/Duchess-Kate-s-royal-baby-bump
/Photo-Galleries/Photos-of-the-Day/2013/Photos-of-the-day-05-14
/Photo-Galleries/In-Pictures/Keffiyeh-is-rebel-chic
/Photo-Galleries/CSM-Galleries/Election2012/Tea-Parties
/Photo-Galleries/In-Pictures/Latin-America-s-fight-against-drugs-and-violence
/Photo-Galleries/Photos-of-the-Day/2013/Photos-of-the-day-05-13
/Photo-Galleries/In-Pictures/Look-up!-The-wonders-of-modern-architecture
/Photo-Galleries/In-Pictures/Exclusive!-with-Barbara-Walters
/Photo-Galleries/In-Pictures/Space-Photos-of-the-Day/Exploring-Mars-with-Curiosity
/Photo-Galleries/In-Pictures/A-chance-to-pray-at-the-Western-Wall
/Photo-Galleries/Photos-of-the-Day/2013/Photos-of-the-day-05-09
/Photo-Galleries/In-Pictures/Making-it-in-Japan
/Photo-Galleries/In-Pictures/Mothers-of-the-world
/Photo-Galleries/In-Pictures/What-happened-at-the-US-Consulate-in-Libya
/Photo-Galleries/Photos-of-the-Day/2013/Photos-of-the-day-05-08
/Photo-Galleries/In-Pictures/Istanbul-A-tale-of-two-cities
/Photo-Galleries/In-Pictures/Pakistan-caught-between-ancient-and-modern-life