(AP Photo/Jeff Roberson, File)
Hanaway, a Republican, had strongly considered entering the race. Instead, she intends to remain the U.S. attorney in eastern Missouri until a new president takes office in 2009.
"I love the job, I love my family," Hanaway said in a telephone interview.
"I've made commitments to both of them, and I don't want to shortchange either."
Hanaway's decision to bow out of the race leaves Senate President Pro Tem Michael Gibbons as the only Republican standing in what once figured to be a hot, three-way primary.
Gibbons plans to officially announce his candidacy Saturday, starting at his Kirkwood home, then at fly-around stops in Columbia, Kansas City and Springfield.
State Sen. Chris Koster, of Harrisonville, who also has been campaigning for attorney general, switched to the Democratic Party in August.
Hanaway, 43, of Warson Woods, acknowledged she had been weighing a campaign for Missouri attorney general since the day after the 2004 election. Deciding not to pursue it was "probably the hardest decision of my life," she said.
"I think I owe it to the taxpayers and the career employees here to see things through to the end of my term," Hanaway said.
Another benefit of remaining in St. Louis, instead of embarking on a statewide campaign, is that Hanaway gets to spend more time with her daughter Lucy, 9, and son, Jack, 5.
"That's a very big factor," she said. "I get that Lucy is three years away from the beginning of the teenage years, and that those are a very precious three years."
Hanaway said she informed Gibbons on Monday that she would not be running against him. Gibbons said he sighed with relief.
"We're ready to move forward, and we're committed to the race, but this is just a much better way to go," Gibbons said. "It's much better for the Republican ticket" not have a contested primary.
Although no one else has stepped forward, Hanaway's decision does not guarantee Gibbons a free ride on the Republican side. Official candidacy filing does not begin until February.
Missouri's current attorney general, Democrat Jay Nixon, is not seeking re-election because he is challenging Republican Gov. Matt Blunt in the 2008 elections.
Two Democratic House members who are attorneys -- Jeff Harris, of Columbia, and Margaret Donnelly, of St. Louis -- already have entered the 2008 attorney general's race. Koster has not officially declared his candidacy, but he has been aggressively raising money.
Koster spokeswoman Elisabeth Smith said his campaign finance reports due next Monday at the state Ethics Commission will show Koster has more than $1 million on hand.