Israel also worries that the ongoing campaign against the Islamic State will come at the expense of the critical struggle against Iran's nuclear program.

Fighting the Islamic State is vital and Israel unequivocally supports the global effort to prevent the formation of a new Islamic caliphate in the Middle East. But even more important is the imperative to preclude the already existing Islamic Republic of Iran — with its infamous track record of sponsoring terrorist groups, abusing human rights, calling for Israel’s destruction, and lying unabashedly for almost 20 years about its nuclear program — from acquiring a nuclear weapons capability.

Many experts argue that because a deal with Iran would necessarily include some restrictions on the Iranian nuclear project, an imperfect agreement is better than no agreement. They are wrong.

That’s because Iran has already made considerable progress in its attempt to advance toward nuclear weapons. An agreement that allows Iran to continue circling in a holding pattern will resemble what happened with North Korea after the 2007 agreement left large parts of Pyongyang’s nuclear capabilities intact, which enabled the North Koreans to produce several nuclear weapons in the following years. Under such conditions, nothing will stop Iran’s mullahs from landing, sooner or later, at their ultimate destination.

Second, a flawed deal would hand Iran practical advantages in return for almost nothing. In return for an insignificant and temporary reduction of its enrichment capacities, Iran stands to reap $100 billion per year when the sanctions are lifted; gain formal legitimacy for its uranium enrichment activities; and, despite its history of nuclear fraud and concealment, preserve the capability to produce nuclear weapons at a time it deems appropriate. Three factors will determine the breakout time needed for Iran to produce nuclear weapons: the quantity and quality of its remaining operational centrifuges; the amount of 3.5 percent enriched uranium that it is permitted to stockpile; and the final destiny of its remaining centrifuges and their infrastructure. The international community must have full and complete clarity on these fundamental issues.