President Obama greets a woman at Wazee Supper Club in Denver on Tuesday. He was in Colorado this week speaking about the economy and raising money for congressional candidates. Jacquelyn Martin/AP hide caption

itoggle caption Jacquelyn Martin/AP

Colorado Republican Congressman Cory Gardner after he announced his candidacy for U.S. Senate in March. He's challenging incumbent Democratic Sen. Mark Udall. Chris Schneider/AP hide caption

itoggle caption Chris Schneider/AP