Angela Caragan's A Cupcake Co. offers gourmet cupcakes for special events. Like more than 20 million other small-business owners in the U.S., she has no employees. Courtesy of Angela Caragan hide caption

itoggle caption Courtesy of Angela Caragan

Tourists walk near shops in the Maine seaside village of Northeast Harbor. Dina Rudick/Boston Globe via Getty Images hide caption

itoggle caption Dina Rudick/Boston Globe via Getty Images

Hedge fund manager Paul Singer of Elliott Management has donated $1 million to Mitt Romney's superPAC. Lucas Jackson/Reuters/Landov hide caption

itoggle caption Lucas Jackson/Reuters/Landov

Republican Senate candidate Richard Mourdock (right) speaks with potential voters on March 31 in Evansville, Ind. Tamara Keith /NPR hide caption

itoggle caption Tamara Keith /NPR

Romney sits in a 1962 Rambler American, a 60th-birthday present from his son, on March 12, 2007, at his home in Belmont, Mass. Romney's father, George Romney, was president of American Motors Corp., which built the car. AP/Courtesy of Tagg Romney hide caption

itoggle caption AP/Courtesy of Tagg Romney

Republican presidential candidate Mitt Romney campaigns in Muskego, Wis., on Saturday. Steven Senne/AP hide caption

itoggle caption Steven Senne/AP