Maryland Democratic Sen. Barbara Mikulski is announcing her retirement today, creating the second open seat of the cycle. Mikulski was elected to the U.S. House in 1976 and to the U.S. Senate in 1986, making her the longest serving woman in Congress. The results of last year's gubernatorial contest notwithstanding, Maryland is a solidly blue state and the Republican bench is especially weak. The race here is going to be the Democratic primary. U.S. Reps. Donna Edwards and Chris Van Hollen are both expected to run, though neither has announced. Other Democrats are certain to at least look at the race. The contest will remain in the Solid Democratic column.

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