New York ? ABC on Tuesday appointed George Stephanopoulos to anchor “This Week,” and the former Clinton aide urged those who question his objectivity to watch him with an open mind on Sunday mornings.

The network also named a new chief executive, Jon Banner, for the public affairs program, which dominated Sunday mornings a decade ago but now struggles in the long shadow of NBC’s Tim Russert.

Stephanopoulos

Stephanopoulos, already a panelist on the program, will replace Sam Donaldson and Cokie Roberts shortly after Labor Day.

Roberts announced earlier this spring that she was quitting, after media reports circulated that Stephanopoulos was in line for the job.

Donaldson will report for ABC’s “Nightline” and the network’s newsmagazines.

Behind television veteran David Brinkley, ABC spent many years atop the Sunday morning pack. In 1997, the year after Brinkley retired, “This Week” and NBC’s “Meet the Press” were virtually neck-and-neck in the ratings.

So far this season, “Meet the Press” averages 4.7 million viewers each week, or 46 percent more than “This Week’s” 3.2 million. CBS’ “Face the Nation,” with a little more than 3 million viewers, occasionally beats ABC for second place.

Stephanopoulos, since being hired at ABC News in 1996, has tried a variety of commentator, anchor and reporting roles before settling into covering the political world he knows well.

“George has demonstrated over his time here a great ability to understand complex issues and explain them in simple terms to the audience,” ABC News President David Westin said.

“He’s a very good communicator. He knows Washington. He knows public policy very well. He’s done everything we’ve asked him to do. He’s shown a real facility and a real growth curve.”

As a former spin doctor for the Clinton campaign and presidency, Stephanopoulos’ political role was more visible than most.

“I think I’ve shown in my work and will continue to show that I’m a tough but fair interviewer,” Stephanopoulos said. “I’m not going to bring any bias to the table. I’m going to do what I can to make sure that people have the full picture.

“The questions are fair,” he said. “I just hope that people will watch with a fair mind.”

It remains to be seen whether Stephanopoulos’ background will handicap ABC’s ability to get top GOP interview guests in a TV format where the networks compete heatedly.

A spokesman for the Republican National Committee said that he’s willing to give Stephanopoulos a chance.

“We look forward to working with him,” Kevin Sheridan said. “Obviously, everyone knows his past. He’s a true liberal and doesn’t hide the fact. We’re hoping he grows into the role of prime-time journalist.”