Illinois Attorney General Lisa Madigan announced Monday that she would run for reelection rather than for governor, taking out one of vulnerable Gov. Pat Quinn's potential primary rivals.

In a statement, Madigan said that her father's decision to stay in his post as speaker of the Illinois House was the driving force behind her decision. 

"I feel strongly that the state would not be well served by having a governor and speaker of the House from the same family and have never planned to run for governor if that would be the case," she said in a statement. "With Speaker Madigan planning to continue in office, I will not run for governor."

Michael Madigan has held the speakership for all but two years of the past two decades; he's also the state Democratic party chairman. His powerful role in the state has always been both a blessing and a curse for his daughter's political career. And in recent weeks, he's been involved in an alleged patronage scandal.

That leaves Quinn in the Democratic primary with former White House chief of staff Bill Daley, who had polled voters on the family connection and found that it hurt Madigan's standing.

It's a big opening for Daley, the brother of former Chicago mayor Richard Daley.

"General Madigan's decision not to run now gives voters a clear choice between a proven leader who gets things done and a governor who can't seem to get anything done," said Daley spokesman Pete Giangreco.

Madigan would have been the heavy favorite in the race had she decided to run -- she's raised more money than Quinn or Daley combined, and several polls had her leading Quinn by a wide margin.