By Nadine Elsibai
Dec. 14 (Bloomberg) -- Senator Tim Johnson underwent brain surgery overnight at George Washington University Hospital in Washington, leaving him in critical condition, said an aide to the lawmaker who wished to remain anonymous.
Johnson, 59, a Democrat from South Dakota, was taken by ambulance to George Washington Hospital in Washington yesterday afternoon after becoming disoriented during a conference call with reporters. His office issued a statement saying he had had a ``possible stroke.'' Control of the new U.S. Senate may now depend on Johnson's health after Democrats won a 51-49 majority in the Nov. 7 midterm elections. If Johnson's seat were to become vacant, South Dakota Governor Mike Rounds, a Republican, may appoint a Republican replacement.
That would shift the partisan balance to 50-50 and give Republicans control through the tie-breaking vote of Vice President Dick Cheney.
Further details on Johnson's condition are expected later this morning, the aide said.
Johnson is one of 26 Democratic senators whose death or incapacity would jeopardize Democrats' control of the chamber because their successor would be appointed by a Republican governor. That number will fall to 18 in January when the governorships of Arkansas, Colorado, Maryland, Massachusetts and New York switch to Democratic from Republican control.
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