Neither US President Donald Trump nor Prime Minister Benjamin Netanyahu like the 2015 Iran nuclear weapons deal, also known as the Joint Comprehensive Plan of Action.Last month, Trump told the UN General Assembly the JCPOA was an “embarrassment” and “one of the worst and most one-sided transactions the United State has ever entered into.” Netanyahu’s “fix it or nix it” speech to the same forum presented the same position.We agree with Trump and Netanyahu that the JCPOA is a bad deal. Because it is narrowly worded to make it easier for Tehran to comply, the deal ignores Iran’s continued support for terrorism and endangerment of American and Israeli lives in Lebanon, Gaza, Iraq, Syria and elsewhere; it is silent on the issue of Iran’s development of long-range ballistic missiles that have the sole purpose of carrying nuclear warheads; and, even within the framework of the JCPOA, too much secrecy and a lack of transparency prevent the monitoring of Iran’s development of nuclear explosive devices.Nevertheless, a unilateral decision on the part of Trump to rip up the deal and walk away without a clear alternative is not necessarily in the interest of the US or of Israel, particularly at a time when there is a lack of broad consensus in Washington and around the world.US and Israeli interests would be better served if Trump worked with his White House staff and Congress to articulate a clear policy that includes the wise use of crippling sanctions and more stringent monitoring to ensure that Iran is not developing nuclear weapons.So far, Trump has opted not to scrap the deal. Every 90 days, the US president is faced with the prospect of certifying that “Iran is transparently, verifiably and fully implementing the agreement” and that it is in the US’s interests to keep the JCPOA in place.Twice already he has verified it. He is now facing an October 15 deadline for the third 90-day review since he took office. And, this time, according to media reports, Trump is setting the groundwork for a new approach that has the support of Secretary of State Rex Tillerson and Secretary of Defense James Mattis. Both Tillerson and Mattis oppose the outright scrapping of the deal, but Mattis has said decertification is a “distinct” matter. Trump could decertify without leaving the agreement and in parallel take a numbers of measures. Decertification would start a 60-day clock on which Congress would need to vote on whether to re-impose secondary sanctions or walk away from the agreement altogether.The basis for decertifying the deal would be the US president’s inability to say for sure that Iran is implementing the agreement. That’s because officials from International Atomic Energy Agency – including Yukiya Amano – have admitted that there are sites – including military bases and university research centers – where the IAEA has not received access.True, Iran has not been caught red-handed violating the deal. But the US president’s job is not to prove the mullahs are not implementing the deal, rather it is certify that they are – and that is something he cannot do because IAEA officials do not have free access to all sites.The Trump administration could stop short of demanding a total “snapback” of sanctions that would constitute an American breach of the agreement. Instead, additional sanctions could be implemented in response to Iran’s violation of UN Security Council resolution 2231, which prohibits development of missiles capable of carrying nuclear weapons. (Development of these missiles is not a violation of the strict wording of the JCPOA, but it is inconsistent with the JCPOA’s fundamental purpose, which is to prevent Iran from obtaining nuclear arms capability.) The US could also punish Iran for its continued support for Hezbollah and Hamas, which are both deemed to be terrorist organizations by the US and many other Western countries, and for endangering the lives of US military personnel in Iraq and in Syria.To confront Iran effectively, Trump has to work to build a strong consensus at home and overseas for whatever he plans to do. Scrapping the deal without putting in place an alternative strategy that at the very least has strong backing in Washington and Europe would give Tehran total freedom to develop its nuclear weapons program. Neither US nor Israeli interests are served by this.