08/29/2011 08:13 am ET Updated Oct 29, 2011

Alison Stewart Leaving 'Need To Know' On PBS

Alison Stewart is leaving her position as co-anchor of PBS' "Need to Know" in September, according to the New York Times.

The hour-long show will debut a new half-hour format this month as well as a new focus on the 2012 election -- both of which swayed Stewart's decision to step down. Her departure leaves "Need To Know" without either of its two original anchors. Stewart was paired with former Newsweek editor Jon Meacham when the show, which replaced "Bill Moyers' Journal" on Fridays, debuted in May 2010. But Meacham left that position in April, becoming a contributing editor. Now, Stewart said that an upcoming book, her family life and the impending truncating of the show all made her decide to leave.

"For a show about politics you have to have someone available and present 110 percent of the time,” she told the Times. “I didn’t feel like I was the right person and that it was the right time to continue with the show."

This is just the latest career move for Stewart, who came to PBS from NPR and has also anchored at ABC, MSNBC and MTV. Her last day is expected to be Sept. 9.