Melissa A. Hart, who once represented a western Pennsylvania district, is one of four former Republican House members seeking to win back a seat lost in 2006, when Democrats gained control of the House.
At least a dozen congressional races -- in Pennsylvania, New Hampshire, Wisconsin, Illinois, Indiana, Washington, New York, Florida, Nevada and North Carolina -- are rematches.
On the Democratic side, six challengers who lost to the now-Republican incumbent two years ago are giving it another try.
Hart blames her loss to Democrat Jason Altmire on voters' unhappiness with the Iraq war, scandals on Capitol Hill and an unpopular incumbent GOP senator at the top of the ticket. With more stability in Iraq, Hart said, the climate has changed dramatically.