Ruth Harkin, right, with Iowa Sen. Tom Harkin.
DES MOINES, Iowa (CNN) - Ruth Harkin, the wife of Iowa Sen. Tom Harkin, will back Sen. Hillary Clinton in the race for the Democratic presidential nomination, a well placed source tells CNN.
This is a major endorsement for Clinton, who only weeks ago had come under fire from some Iowa Democrats after one of her senior campaign staffers suggested the New York senator should skip Iowa and invest time and money in other early voting states. Clinton disavowed the advice laid out in a memo leaked to the news media and is campaigning in the Hawkeye State this week with her husband, former President Bill Clinton.
"This is personal for her," said the source of Ruth Harkin's decision to endorse Clinton. The source added that Ruth Harkin is feeling very strongly about the New York Democrat's candidacy.
Harkin's husband will stay neutral in the race, added the source, who spoke on the condition of anonymity.
Ruth Harkin served President Clinton's administration as president of the Overseas Private Investment Corporation. She was the first woman elected to the position of county attorney in Iowa, when she took office in 1972 in Story County.
- CNN Senior Political Correspondent Candy Crowley