Texas Republican Kay Bailey Hutchison confirmed Wednesday that she will resign her U.S. Senate seat this fall to concentrate on her March 2010 primary challenge to Republican Gov. Rick Perry.

Kay Bailey Hutchison (CQ/Scott J. Ferrell)

The move by Hutchison — which was not unexpected — will necessitate a special election next spring, almost certainly in early May to fill the remainder of her Senate term. The next regularly scheduled election for the seat is in 2012.

Hutchison told Texas radio interviewer Mark Davis that she will leave the Senate in October or November, vacating a seat she has held since she won a 1993 special election. She subsequently won re-election three times.  

She plans to make a formal announcement next month that she is making her long-expected bid for governor in a contest that will pit her against Perry, who was elected to full terms in 2002 and 2006 after moving up from lieutenant governor in 2000 to fill the vacancy caused by incumbent Republican Gov. George W. Bush’s election to his first term as president.