The Iran nuclear deal is broken and is, as President Trump noted in speaking to the United Nations, an embarrassment. But on Oct. 15, the next deadline for his assent or dissent, he should nevertheless certify Iran's compliance.

This seems contradictory and appeasing, but it isn't. It's sensible diplomacy based squarely on a results-based calculation about the best way to force Iran to do what we need them to do.

Decertifying Iran now would make fixing the nuclear deal much harder because it would create greater friction between the U.S. and its European allies and thus make it harder to draw them into a coalition to put pressure on the mullahs.

If the end-objective is a nuclear deal that restrains Iran's threat, then, short of military force or a transatlantic rift, European participation in Trump's deal reform is preferable.

We propose an alternative approach. Come Oct. 15, President Trump should certify Iranian compliance, but lay out clear and concrete ways in which the deal must be improved if it is to survive.

First, it must be changed to remove an exigent flaw that it enables rather than restrains Iranian ballistic missile research. It enables that research because by granting Iran post-deal sanctions relief, the regime has more money to spare. In turn, using the launch of satellites as a cover story, Iran is aggressively developing a competent ballistic missile capability. Trump should proclaim to the world that Iran's missiles do not simply portend a future nuclear holocaust, but also threaten to start a nuclear arms race in perhaps the most volatile region of the world. Trump must demand that Iran's ballistic missile program be restricted.

Second, the president should commit to a tightening of the deal's inspections framework. Here, the president should point to Iran's repeated refusal to open its military sites to inspectors, as promised. Next, Trump should demand an end to Iran's right to delay IAEA inspector access to certain sites for up to 24 days. This egregious loophole facilitates Iran's endless and utter dishonesty.

The president must make clear that if these two concerns are not addressed, he will decertify the Iran deal on the next 90-day deadline, Jan. 13, 2018.

His expectations established, Trump should then woo the Rouhani bloc of the Iranian government. He could state that he does not believe the tightest restrictions need to be extended beyond 2025, and that upon that date, Washington would negotiate a new deal.

As Iran's supreme leader, Ayatollah Khamenei, is unwell and old, and because who knows who his successor will be or what beliefs he will hold, it is better to have a reformed deal than to destroy it. The U.S. military will continue to outmatch Iran in 2025 and for the foreseeable future beyond that.

On Oct. 16, Trump should launch an urgent diplomatic campaign to win European support for his proposals. His primary focus must rest on Prime Minister Theresa May of Great Britain and President Emmanuel Macron of France, whose support is a prerequisite for that of German Chancellor Angela Merkel.

While some say appealing to Europeans is delusional, we disagree and note, for example, the French government's August statement that the Iran deal requires new "indispensable work on the use of ballistic missiles."

Trump will, however, need to carry a big stick to his talks with Europe. He must explain that if they do not join him in twisting Iran's arm and improving the deal, he will decertify it on Jan. 13 and ask Congress to impose heavy sanctions on European multinationals doing business with Iran. We are confident that this will prompt a sense of urgency in the chancelleries of Europe.

Finally, between Oct. 15 and Jan. 13, Trump will have to strengthen America's deterrent posture towards Iran. He should point out that while he is a "dealmaker," he is also the world's most powerful commander-in-chief. To deter Tehran from disrupting renegotiation efforts, Trump should make it plain that his options run considerably beyond diplomacy and economic sanctions. He might, for example, point to his Defense Secretary's 2015 threat of a naval blockade.

Time is not on America's side. As each month passes, European investors become more deeply intertwined into the Iranian economy, and their political leaders less amenable to confronting Iran. With each passing month, Iran's ballistic missile capabilities grow stronger and the hardliners ambitions bolder.

The Trump administration has repeatedly demonstrated how damaging it is to act in haste and repent at leisure. The "travel ban" comes to mind; it was ill-considered and incompetently executed, and thus blew up in the president's face. Taking the proper time to put things in place — that doesn't mean dawdling or wasting time — can lead ultimately to a more effective policy being put in place faster.

Decertifying Iran on Oct. 15 would hurt, not help, Trump's appropriate and urgent pursuit of a better deal.