Washington (CNN) - Sources confirm to CNN that Democratic Rep. Parker Griffith will announce Tuesday that he's switching parties and will run for re-election next year as a Republican.
The freshman lawmaker represents Alabama's 5th Congressional District. Griffith won his seat last year by 3 points over Republican Wayne Parker. But the district went for Republican John McCain over Barack Obama by 23 points in the presidential election.
The Republican source was familiar with the decision but didn't want to preempt the announcement later Tuesday. The story was first reported by Politico. A Democratic aide also tells CNN Griffith is holding a staff meeting Tuesday morning to inform his staff of his decision, and will make a formal announcement at 2 p.m. ET.
Griffith was one of 39 Democrats who voted against the party's health care reform bill last month. His is only one of three Democrats to have voted against the health care bill, the stimulus measure, and the cap-and-trade bill.
Griffith pledged in August he would vote against House Speaker Nancy Pelosi as Speaker next session.
With Griffith's switch of parties, the Democrats will hold a 257-178 advantage in the House of Representatives.
– CNN's Evan Glass and Paul Steinhauser contributed to this story