Former U.S. ambassador to Israel Martin Indyk forecasts that the United States will go to war with Iran next year over its nuclear program.

Speaking during a panel discussion Sunday on the CBS program Face the Nation, Indyk said: "I'm afraid that 2013 is going to be a year in which we're going to have a military confrontation with Iran."

Indyk, currently head of foreign policy at the Brookings Institute think tank, said that "Iran doesn't have a nuclear weapon," but added that there's not a lot of time left until it does.

"There is still time, perhaps six months, even by Prime Minister [Benjamin] Netanyahu's own timetable, to try to see if a negotiated solution can be worked out," Indyk said.

Regarding the recent friction between U.S. President Barack Obama and Netanyahu over "red lines" on Iran, Indyk said that he doesn't think "the difference between Netanyahu and Obama on this is that great, in terms of the president's commitment not to allow Iran to acquire nuclear weapons."

He added, however, that Netanyahu's insistence on public "red lines" was unreasonable.

"That is an unreasonable requirement. The idea of putting out a public red line  in effect issuing an ultimatum  is something that no president would do. If you noticed, Governor Romney is not putting out a red line; Senator McCain didn't, either. And neither is Bibi Netanyahu for that matter, in terms of Israel's own actions," Indyk noted.

He went on to speak about instability across the Middle East, saying it is making Israel "very nervous."

"The turmoil we see from here, they see from a much closer perspective, and that combines with the, as the prime minster puts it, the race of Iran towards weapons capability. The fear that the Egypt-Israel peace treaty will start to come apart, the concern that in Syria what is happening there could lead to an Islamist government taking over eventually there as well, but before that a descent into chaos on the northern border all that makes them very nervous and that's why I think the prime minister is coming out much more vocally than one might have expected in the midst of an election campaign here saying, you know, we need reassurances, we need red lines against the Iranians because from his point of view, that's the greatest threat they face", Indyk said.

Netanyahu warned on Sunday that Iran would reach the brink of nuclear  weaponscapability in six to seven months, adding new urgency to his demand that Obamaset a clear "red line" for Tehran, a demand that could deepen an already substantial U.S.-Israeli rift.

Taking his case to the American public, Netanyahu said in U.S. television interviews that by mid-2013, Iran would be 90 percent of the way toward generating enough enriched uranium for a bomb. He urged the United States to spell out limits that Tehran must not cross on pain of facing military action  something Obama has refused to do.

"You have to place that red line before them now, before it's too late," Netanyahu told NBC's "Meet the Press" program, saying that such a move could reduce the chances of having to attack Iran's nuclear sites.