Here and in Washington, officials assume that as soon as information is received that Iran has moved to build nuclear weapons, Israel will decide to attack its nuclear facilities. Therefore, any exchange of intelligence between Israel and the United States could have far-reaching consequences for the Middle East — and the world.

In other words, the momentous decision will be driven to an extraordinary extent by intelligence reports…

Both Israel and America should acknowledge that scraps of information cannot serve as the basis for action against Iran, and they should find new criteria for such a decision.

The direct talks that begin on Friday in Istanbul offer a chance to develop at least some new measures of Iran’s willingness to cooperate. This could work on two levels. Publicly, Iran can be judged on its willingness to meet the world’s demands. Under the surface, a continuing dialogue between Iran and the West — which will require much consultation and interaction among Iranians themselves — can reveal or clarify information about Iran and its decision making that would not have surfaced otherwise.