Israeli Prime Minister Benjamin Netanyahu presents material on Iran’s purported nuclear program in Tel Aviv on Monday. (Sebastian Scheiner/AP)

AS PRESIDENT Trump approaches his May 12 deadline for deciding whether to abrogate the Iran nuclear deal, allies are lining up to lobby him — something our attention-craving president no doubt is savoring. Last week the French and German leaders trekked to the White House to make their pro-pact cases; now, via televised address, comes Israel’s Benjamin Netanyahu, one of the accord’s most determined opponents. Mr. Netanyahu had something unique to offer: a trove of Iranian documents outlining work on nuclear arms, pilfered by the Mossad from a Tehran warehouse in January. What he didn’t have was a coherent case for why the deal should be scrapped.

Mr. Netanyahu described the capture of what he said was “half a ton” of secret Iranian nuclear archives as “one of the biggest intelligence achievements ever by the state of Israel.” That may be true, but judging from what Israel has released so far, the trove doesn’t add greatly to what was already known about Iran’s pursuit of nukes. As the International Atomic Energy Agency (IAEA) and U.S. intelligence agencies reported years ago, the Islamic republic sought to build a weapon until 2003, when it put the project on hold while still pursuing dual-use activities, such as uranium enrichment. These, in turn, were curbed by the 2015 agreement, which strictly limits enrichment until the mid-2020s.

Mr. Netanyahu argued that Iran violated the deal by lying to the IAEA about its previous pursuit of a weapon. But that, too, was well known. The real purpose of the pact was to curb Tehran’s future activity, at least for a decade or so. Multiple IAEA reports and even the Trump administration have confirmed that, on that score, Iran has complied. That’s why Mr. Netanyahu’s own top national security officials support the agreement; the Israeli army’s chief of staff recently said , “Right now, the agreement, with all its flaws, is working and putting off realization of the Iranian nuclear vision by 10 to 15 years.”

Why would the Israeli prime minister wish to forgo that respite? Perhaps because his government is already engaged in a slow-burning military conflict with Iran. On Sunday, an apparent Israeli airstrike targeted a store of Iranian missiles deep inside Syria, in the second such attack in the past three weeks. Mr. Netanyahu has said Iran is seeking to entrench itself in Syria, and he has been seeking U.S. help to prevent it. So far he has been unsuccessful: Mr. Trump keeps restating his intention to end the U.S. mission in Syria. Yet if the president scraps the nuclear deal, the United States could be drawn into a conflict with Tehran.

Mr. Trump has been coy about his intentions, allowing suspense to build, but he seems strongly inclined to withdraw from the accord. It’s not clear he has studied the merits of doing so, or the possible consequences; on Monday he grossly misstated the terms of the deal, saying that, under it, “in seven years . . . Iran is free to go ahead and develop nuclear weapons.” (In fact, Iran is permanently banned from developing nukes.) Mr. Trump has frequently said he does not want the United States to fight more Middle East wars. If so, it would be in his interest to look beyond Mr. Netanyahu’s video appeals before making a final decision.