On the Trail

Democratic presidential hopeful New York Sen. Hillary Rodham Clinton arrives on stage to address trade union members and representatives at the Building Trades National Legislative Conference at the Washington Hilton hotel.  (Robyn Beck / AFP/Getty Images)

Democratic presidential hopeful Sen. Barack Obama (D-Ill.) speaks at the Philadelphia City Committee dinner.  (Jae C. Hong / Associated Press)

Cindy McCain, wife of candidate John McCain, poses for a picture with supporters of her husband at Cecil Field in Jacksonville, Fla.  (Jake Roth / Associated Press)

Stephen Colbert, host of Comedy Central’s “The Colbert Report,” is seen with Michelle Obama, wife of presidential hopeful Barack Obama, during taping at the University of Pennsylvania.  (Matt Rourke / Associated Press)

Former President Bill Clinton speaks to a crowd gathered at Bellmont Middle School in Decatur, Ind., during a campaign stop on behalf of his wife and presidential candidate, Sen. Hillary Rodham Clinton.  (Clint Keller / Associated Press)

Sen. Hillary Rodham Clinton takes questions from the audience at the Newspaper Assn. of America convention in Washington, D.C.  (Charles Dharapak / Associated Press)

Sen. John McCain speaks at an economic summit at Bucyrus International Inc., in South Milwaukee, Wis.  (Mary Altaffer / Associated Press)

US Democratic presidential candidate Illinois Senator Barack Obama during a veterans town hall meeting at Washington and Jefferson College in Washington, Pennsylvania.  (EMMANUEL DUNAND, AFP/Getty Images)