They may not know when a special election will be held, but would-be successors to Texas Republican Sen. Kay Bailey Hutchison continue to raise campaign funds with the expectation that she’ll soon vacate her seat to concentrate on her 2010 campaign for governor.

The candidates want to be ready for a speedy balloting that is expected to take place in May, though the Texas election statutes also give Republican Gov. Rick Perry some discretion in setting a date.

Hutchison, who is challenging Perry for the GOP nomination in a March primary election, said in July that she would resign in October or November. But that plan appears to have fallen by the wayside: she said last week that she is “going to leave” but wasn’t sure exactly when.

Though Republicans have dominated recent statewide elections in Texas, GOP officials acknowledge that an atypical special election could be very competitive. And at the moment, the best-funded candidate for Hutchison’s seat is a Democrat, Houston Mayor Bill White, who took in more than $1.5 million in this year’s third quarter and $6 million for his campaign to date. More than $400,000 of White’s third-quarter receipts and $1.4 million of his overall receipts came from the his own pocket.