John McCain on the Iowa trail

New York City, March 8 2007: Senator McCain speaks at a McCain Exchange Forum in the Millennium Broadway hotel Photograph: Mario Tama/Getty

Manchester, New Hampshire, April 25 2007: McCain officially announces his bid for the presidency with a campaign rally and kicks off a four-day tour with stops in South Carolina, Iowa, Nevada and Arizona Photograph: Justin Sullivan/Getty

Portsmouth, New Hampshire, April 25 2007: A McCain supporter carries a sign as he waits for the senator to arrive at a rally Photograph: Justin Sullivan/Getty

Portsmouth, New Hampshire, April 25 2007: McCain and his wife Cindy step off his campaign bus before the start of a rally Photograph: Justin Sullivan/Getty

Kansas City, 20 Aug 2007: McCain gets a hug from Sherman L Jones, a Korean war veteran from Texas, after speaking to a group of veterans at the 108th National Convention of Veterans of Foreign Wars of the US Photograph: Larry W. Smith/EPA/Corbis

Johnston, Iowa, December 12 2007: Republican presidential hopefuls Mike Huckabe (l), John McCain and Rudy Giuliani (r), before the Des Moines Register Republican presidential debate. Photograph: Charlie Neibergall/AP

Spartanburg, South Carolina, December 11 2007: McCain, his mother Roberta and former Texas senator Phil Graham wave to the crowds as they take part in a Christmas parade Photograph: Mary Ann Chastain/AP

Greenville, South Carolina, April 26 2007: Supporters listen to McCain at a rally Photograph: Justin Sullivan/Getty

Davenport, Iowa, May 7 2007: McCain addresses a meeting of Iowa Republicans Photograph: Charlie Neibergall/AP

Salem, New Hampshire, December 18 2007: Meghan McCain, daughter of the senator, waves as she is introduced by her father during a campaign stop Photograph: Jim Cole/AP

Gladbrook, Iowa, September 2 2007: McCain speaks during a house party Photograph: Charlie Neibergall/AP

Pelham, New Hampshire, December 20 2007: People sign in as they arrive to hear McCain speak at a campaign event at Pelhan High School Photograph: Darren McCollester/Getty

Simi Valley, California, May 3 2007: McCain participates at the first Republican Candidates' debate of the 2008 Presidential Race, at the Reagan Presidential Library Photograph: Gabriel Bouys/AFP

Orlando, Florida, February 18 2007: Bumper stickers for sale during the National Religious Broadcasters convention Photograph: Joe Raedle/Getty

Vero Beach, Florida, February 19 2007: McCain delivers a stump speech as he visits the Community Church Photograph: Joe Raedle/Getty

Washington, DC, February 1 2007: Hillary Clinton and McCain listen to President George Bush speak during the National Prayer Breakfast Photograph: Brendan Smialowski/AFP

Hillsborough, New Hampshire, December 17 2007: Senator Joseph Lieberman, a former Democratic vice-presidential candidate, announces his endorsement for McCain Photograph: Jim Cole/AP

Washington, DC, September 21 2007: McCain addresses a National Rifle Association meeting Photograph: Chip Somodevilla/Getty

Boston, Massachusetts, December 19 2007: McCain speaks to reporters at Faneuil Hall while former secretary of state Dr Henry Kissinger looks on Photograph: Darren McCollester/Getty