Deep divisions in Washington obscured a shared objective: preventing Iran from obtaining nuclear weapons. That goal is closer to reality thanks to Thursday's Senate vote on the Joint Comprehensive Plan of Action, more commonly known as the Iran deal.

Too often lost in the binary domestic debate has been the fact that this is a multinational accord. Rejecting it would have risked the hard-fought global unanimity on sanctions that brought Iran to the table in the first place.

If the deal had been blocked in Congress, the sanctions regime likely would have unraveled, and Iran would have continued to be months, not years, from being able to develop a nuclear weapon. China and Russia probably would have bolted from the P5+1 coalition of permanent members of the U.N. Security Council, and Britain, France and Germany (the +1) also would have been unlikely to reimpose sanctions.

U.S. unilateralism, not Iranian fanaticism, would have been blamed if this rare diplomatic success had unraveled. That could have precluded any future breakthroughs at a time when the world is contending with spiraling crises, including the flood of migrants destabilizing countries and continents.

Diplomacy should always be the first option. If Iran cheats, there are "snapback" options for sanctions. And accepting and testing hard-fought diplomatic gains does not mean that military options no longer exist.

There should be no naiveté about the nature of the theocracy ruling Iran, which has brutalized its own people and destabilized multiple Mideast countries. It's legitimate to fear that funds from sanctions relief could be funneled to regional extremists. Accordingly, the Obama administration has offered to bolster military capabilities of Gulf allies and further strengthen the unbreakable U.S.-Israel alliance.

It's crucial to convey that acceptance of the deal does not mean acceptance of Tehran's provocations, which is why sanctions on that behavior will remain.

Israel rightly regards Iran as an existential threat, and it's understandable that many Israelis have grave concerns. But justifiable fear over Iranian intentions is precisely why it's imperative that Iran not get a nuclear weapon.

"We are confident that the agreement provides the foundation for resolving the conflict on Iran's nuclear program permanently," British Prime Minister David Cameron, French President Francois Hollande and German Chancellor Angela Merkel wrote in a Washington Post commentary published Thursday. And the three U.S. allies got to the heart of the diplomatic matter when they wrote: "It is a crucial opportunity at a time of heightened global uncertainty to show what diplomacy can achieve."

This deal, however imperfect, is the best method to do that.