"My sense is the Pentagon would be worried or opposed to an Israeli attack," says David Wurmser, former Middle East adviser to Vice President Dick Cheney, who left the White House job late last summer. "They are afraid it would inflame the situation in Iraq, which could undermine the US position there.

"Ultimately, my gut tells me that most of the administration on most levels would push back very hard," on Israeli pressure on Washington to authorize it to strike Iran, Wurmser added. "What those in the administration who don't want Israel to act probably won't want is for it to be taken to the highest level. They would always be afraid that [the president] might not be so tough on the Israelis. If the Israeli [government] really intends to do something, they would go to the highest level without a lot of people knowing."

Last week, the chairman of the Joint Chiefs of Staff Admiral Michael Mullen visited Israel, during which Mullen is reported to have told Israeli leaders that, speaking for the highest levels of the Bush administration, they did not have a green light from Washington for military action on Iran. Now, Mother Jones has learned, a parade of senior Israeli government officials is making its way to Washington over the coming two weeks, to discuss the Iran issue with top Bush administration officials. Among those scheduled to arrive, Mother Jones has confirmed with Israeli sources in Washington and Israel: Israeli defense minister Ehud Barak, who departs Israel Monday for meetings in Washington with President Bush, Vice President Cheney, and Pentagon officials; and the Israeli Defense Forces chief of staff Gabi Ashkenazi, who comes the following week on his first visit to Washington in that position. A former Pentagon intelligence official who spoke with Mother Jones also alleges that Meir Dagan, the chief of the Israeli intelligence service, the Mossad, held secret meetings with officials in the White House on Wednesday. Neither the Israeli embassy nor National Security Council would comment on whether Dagan had been at the White House.

US sources who did not wish to be identified describe a disagreement between the US and Israeli intelligence communities over the timetable of Iran's alleged weaponization and research and development efforts. Nuclear analysts at Livermore nuclear facility crunched the numbers and looked at the information on Iran's centrifuges and concluded that they are sticking to the public estimates in the 2007 US National Intelligence Estimate on Iran's nuclear program, which forecast Iran could have enough enriched material for nuclear weapons capability in the mid next decade. The Israelis allegedly presented the US with Iranian weaponization evidence that they consider very credible, which the US intelligence community allegedly did not consider credible. Analysts also say Israel and the US are drawing different definitions and redlines about what they consider would be Iran's nuclear "breakout" capability.

"The last report from the [International Atomic Energy Agency] IAEA suggested that the Iranians are making considerable advances, and could reach a stage of having a mass of material for breakout capability before terribly long," says Patrick Clawson, an Iran policy expert at the Washington Institute for Near East Policy. How long? "It's hard to say. Iran already has fuel rods shipped by the Russians. If they decided to just take that material and run it through centrifuges, that activity would be very obvious.

"What most people concentrate on is when Iran would have 600 to 700 kilos of its own low enriched uranium, which is enough to make enough highly enriched uranium for a bomb," Clawson added. How long is that projected to take? Clawson: "If everything works perfectly, two months. If everything doesn't work perfectly, a bit longer. The answer would be the space of a few months.

"It certainly appears from the last [IAEA] report that Iran is on track to have enough kilos [of low enriched uranium to enrich to weapons grade] within a year—well within," Clawson added.

Adding to Israeli concern, Clawson and Wurmser said, is uncertainty over whether the next US administration will be willing and able to get organized on Iran policy quickly enough to meet Israeli concerns about Iran's nuclear progress as the calendar advances.

"Even beyond the question of whether McCain or Obama wins, the Israelis are afraid that no new administration is really going to be able to get its act together quickly to be able to mobilize a plan and do something," Wurmser said.

Wurmser put the odds of Israel striking Iran before Bush leaves office at "slightly, slightly above 50-50."

Wurmser said that different pressures weigh for and against Israeli military action either before or after the US election in November, but before Bush leaves office. "Israelis may think politically they don't want to get in a situation to do something that causes a reaction against US forces in Iraq, which causes the Republicans to lose the election." But acting after the elections would deeply complicate Israeli relations with the incoming administration.

Wurmser posits a third possibility. "The Israelis may have new information," and that may explain the up-tempo in the high-level US Israeli discussions on Iran. "But a second thing that might explain it is, this is not real. This is pressure to get Bush to act before he leaves."

"A lot turns on details about the assessment not just of Iran's nuclear progress, but also on parts of the Iran program that may not be publicly disclosed and on the projected status of Iran's air defenses or other countermeasures," says one former Bush administration official who asked to speak on background. "I think this also may be a more demanding option operationally than may be apparent from the public debate.

"I've been skeptical of the war talk until recently because I was informed enough to know better," the former official added. "Now I'm not gloomier, just less informed."

Robert Gallucci, a former longtime State Department nonproliferation expert who now serves as dean of Georgetown University's School of Foreign Service, said a recent consultation with US government scientists persuaded him that Iran is not likely to have significant nuclear breakout capability for about five years.

"The test is when Iran could plausibly accumulate significant quantities of highly enriched uranium or plutonium so you have to worry about not only nuclear weapons development, but also the possible threat of transfer to a terrorist organization," Gallucci said Friday.

"I came away [from recent consultations with government scientists] believing that is actually some distance away in time—beyond five years," Gallucci said.

Gallucci said he was talking about when Iran could conceivably produce five or ten or more nuclear weapons. (Iran denies it is seeking a nuclear weapons capability at all, and the 2007 US NIE concluded that Iran had halted its weaponization program in 2003.) Are Israel's threat assessments based on the projection of when Iran could produce one nuclear weapon? "I tend to want to answer that and say there are two ways to come up with a difference [between US and Israeli assessments]. Technically, Israel and the US could have a different assessment of the obstacles that the Iranians might run into and how quickly they could overcome them."

"There could also be a tolerance [difference]," Gallucci said. "We're prepared to say, 'It's unlikely they could do this in this amount of time.' The Israelis could be saying, 'Thank you very much, we're a little closer to the problem than you are.' American national security types are not certain of how quickly Iran could do it, but are just as uncertain about whether Iran would do it or not."

Photo of a B-2 Spirit bomber by flickr user James Gordon used under a Creative Commons license.