Washington (CNN) - Arkansas Rep. Marion Berry is expected to announce Monday that he will not seek re-election and instead retire at the end of the year, two Democratic sources confirm to CNN.
Berry would become the 12th Democrat to announce that he will not run for his House seat again in 2010. Six of those Democrats, including Berry, will not be running for another office, while the other six are either seeking a Senate seat or the governorship of their state.
Berry, a member of the conservative Democratic "Blue Dog" coalition, is currently serving his seventh term and was unopposed in the 2008 election. But Sen. John McCain, the Republican presidential nominee, overwhelmingly defeated then-Sen. Barack Obama in Berry's northeast Arkansas congressional district by a 59 percent to 38 percent margin in last year's presidential contest. Four years earlier, President Bush defeated Sen. John Kerry by a 52 percent to 47 percent spread.
For now, Rick Crawford is the only Republican in the race for Berry's seat, but with his decision to retire, expect others to jump in.
Democratic leaders are keeping a close eye on their colleagues hoping to convince any fence-sitting Democrats to run for re-election in November. Across the aisle, House Republicans face 14 retirements, 11 of whom are running for another office.
The Washington Post first reported that Berry would retire on its Web site Sunday evening.
– CNN's Paul Steinhauser contributed to this report