(CNN) -- The former supreme allied commander of NATO, retired Gen. Wesley Clark, voiced support for President Barack Obama's decision to effectively fire the commander of the Afghanistan war, Gen. Stanley McChrystal.
"I think that there are lines you can't cross and I think there's responsibilities that you have to uphold as a senior commander," said Clark, appearing on CNN's "Campbell Brown" Wednesday.
McChrystal and some of his top aides drew anger from the president after making numerous comments critical of key Obama administration figures in an article appearing in the new issue of Rolling Stone magazine.
"Somehow this got personal. It wasn't a policy issue. It was just personal," Clark told told CNN's John Roberts.
"May have been some guys letting off steam or whatever, but when it got out in the press, it just -- you can't do it."
Asked if could understand the frustration of McChrystal and his underlings, Clark conceded, "It's a tough position. When you're in a senior command position like that, it's very tough. The more you're isolated, the tougher it is... he's under a lot of stress. Sometimes stuff happens."
Clark didn't want to speculate on what might have led to the comments, but told Roberts, "This is a terrible tragedy for him and his family, for the command and for the president. I mean, nobody wanted it to have worked out this way. He had a lot of support in the White House."
As for the president's new choice, Gen. David Petraeus, and the administration's goal of a troop pullout starting in July 2011, Clark described Petraeus as "a great commander, but I don't know (if) he's a miracle worker."
"It's not clear to me, and... I've talked to people, I don't know what the timetable means. Whether it means you've got to pull a brigade out or four brigades out or half the troops out or, you know, an outpost out, i'm not quite clear," Clark said.
"I think the real issue is still to be discerned there... can we muster the kind of good government and overall nation-building prowess and deploy it in a way that it turns back the attractions and threats of the Taliban and the Al Qaeda backing of the Taliban in Afghanistan?"