Otherwise, Iran theoretically could drive a nuclear weapon into Israel by road. But these weapons are not small. There is such a thing as a suitcase bomb, but that is a misleading name; it is substantially larger than a suitcase, and it is also the most difficult sort of device to build. Because of its size, it is not particularly rugged. You don't just toss it into the trunk, drive 1,500 miles across customs checkpoints and set it off. There are many ways you can be captured -- particularly crossing into Israel -- and many ways to break the bomb, which require heavy maintenance. Lastly, even assuming Iran's acquisition of a nuclear weapon, its use against Israel would kill as many Muslims -- among them Shia -- as Israelis, an action tantamount to geopolitical suicide for Tehran.
A Tempered Response
One of the reasons Israel has not attempted an airstrike, and one of the reasons the United States has refused to consider it, is that Iran's prospects for developing a nuclear weapon are still remote. Another reason is difficulty. Israel's air force is too far removed and too small to carry out simultaneous strikes on multiple facilities. If the Israelis forward-deployed to other countries, the Iranians would spot them. The Israelis can't be certain which sites are real and which are decoys. The Iranians have had years to harden their facilities, so normal ordnance likely would be inadequate. Even more serious is the fact that battle damage assessment -- judging whether the site has been destroyed -- would be prohibitively difficult.
For these reasons, the attack could not simply be carried out from the air. It would require special operations forces on the ground to try to determine the effects. That could result in casualties and prisoners, if it could be done at all. And at that the Israelis can only be certain that they have destroyed all the sites they knew about, not the ones that their intelligence didn't know about. Some will dismiss this as overestimating Iranian capabilities. This frequently comes from those most afraid that Tehran can build a nuclear weapon and a delivery system. If it could do the latter, it could harden sites and throw off intelligence gathering. The United States would be able to mount a much more robust attack than the Israelis, but it is unclear whether it would be robust enough. And in any case, all the other problems -- the reliability of intelligence, determining whether the site were destroyed -- would still apply.
But ultimately, the real reason Israel has not attacked Iran's nuclear sites is that the Iranians are so far from having a weapon. If they were closer, the Israelis would have attacked regardless of the difficulty. The Americans, on the other hand, saw an opportunity in the fact that there are no weapons yet and that the sanctions were hurting the Iranians. Knowing that they were not in a hurry to complete and knowing that they were hurting economically, the Iranians likewise saw an opportunity to better their position.
From the American point of view, the nuclear program was not the most pressing issue, even though Washington knew it had to be stopped. What the Americans wanted was an understanding with the Iranians, whereby their role in the region would be balanced against those of other countries, particularly Saudi Arabia, the Arabian emirates and to some extent Israel. As I've argued, the United States is still interested in what happens in the region, but it does not want to continue to use force there. Washington wants to have multiple relations with regional actors, not just Israel and Saudi Arabia.
Israel's response to the U.S.-Iran talks should be understood in this way. The Israelis tempered their response initially because they knew the status of Iran's nuclear program. Even though a weapon is still a grave concern, it is a much longer-term problem than the Israelis admit publicly. (Israeli Prime Minister Benjamin Netanyahu has tried hard to convince the United States otherwise, the United States isn't biting.) Since an attack has every chance of failing, the Israelis recognize that these negotiations are the most likely way to eliminate the weapons, and that if the negotiations fail, no one will be in a more dangerous position for trying. Six months won't make a difference.
The Israelis could not simply applaud the process because there is, in fact, a strategic threat to Israel embedded in the talks. Israel has a strategic dependency on the United States. Israel has never been comfortable with Washington's relationship with Saudi Arabia, but there was nothing the Israelis could do about it, so they accommodated it. But they understand that the outcome of these talks, if successful, means more than the exchange of a nuclear program for eased sanctions; it means the beginning of a strategic alignment with Iran.
