Vermont Sen. Bernie Sanders, an independent, speaks during a December 2012 news conference on Capitol Hill. Sanders said recently he'd consider running for president if no other progressive candidate steps up. Jacquelyn Martin/AP hide caption

itoggle caption Jacquelyn Martin/AP

President Obama meets Friday with immigration activists on the National Mall in Washington. Leslie E. Kossoff/Pool/EPA/Landov hide caption

itoggle caption Leslie E. Kossoff/Pool/EPA/Landov

Commuters wait on the platform as a Metro-North train arrives in Bridgeport, Conn. Craig Ruttle/AP hide caption

itoggle caption Craig Ruttle/AP

Lara Imler has tried to cancel her enrollment on HealthCare.gov, but to no avail. Annie Feidt/Alaska Public Radio Network hide caption

itoggle caption Annie Feidt/Alaska Public Radio Network

President George W. Bush paid a surprise Thanksgiving visit to American troops in Baghdad on Nov. 27, 2003. Pablo Martinez Monsivais/AP hide caption

itoggle caption Pablo Martinez Monsivais/AP

Conservatives have criticized the new Internal Revenue Service rules for political dark money as an Obama administration attempt to gain political advantage. Susan Walsh/AP hide caption

itoggle caption Susan Walsh/AP

New research suggests that increasing numbers of people want to live among those who share their politics. In this April 2010 photo, an aerial view of a Tucson, Ariz., housing development. Charles Rex Arbogast/AP hide caption

itoggle caption Charles Rex Arbogast/AP