There may be more than a few empty seats at this year's Democratic National Convention in Charlotte, North Carolina.

At least three Democratic senators and eight members of the House of Representatives facing tough re-election challenges have opted out of attending this year's convention, which will be held during the week of Sept. 3. Most of the elected officials who have decided to forgo the convention represent so-called "purple" states where President Barack Obama is not popular - such as West Virginia, Utah, Montana and Missouri.

Whether it is because they want to avoid the perceived "stain" of ObamaCare or placate some of their socially conservative constituents, the following is a list of Democratic lawmakers who have decided to distance themselves from Obama on what is arguably the highest-profile event hosted by the nation's Democratic leadership.