Last weekend’s attack on Saudi oil installations merits a significant response. Unfortunately, the Trump administration initially offered only incoherence.

Without offering any evidence, Secretary of State Mike Pompeo said Iran “has now launched an unprecedented attack on the world’s energy supply.” Not to be outdone, President Donald Trump tweeted: “Saudi Arabia oil supply was attacked. There is reason to believe we know the culprit, are locked and loaded depending on verification, but are waiting to hear from the Kingdom as to who they believe was the cause of this attack, and under what terms we would proceed!”

Iran may indeed be responsible, although the Tehran-backed (but not Tehran-controlled) Houthi rebels in Yemen claimed responsibility. Experts are needed to determine the origin of the drone strike in a transparent process, with the conclusions methodically gathered and disseminated.

To every degree possible, this process should be independent and internationalized. “The U.S. certainly has a credibility problem in the region because of the damage that was done politicizing intelligence in the run-up to the Iraq war,” Ali Vaez, director of the International Crisis Group’s Iran Project, told an editorial writer. The administration “also has its own credibility problems given the number of untruths the president has articulated.”

After the initial botched response, Washington and Riyadh have promised transparency. Every nation has an interest in answers. This was an attack not just on Saudi Arabia but also on the world. The damage done to the international energy supply has already spiked prices in a precarious global economy.

“I wouldn’t call this an act of war, I’d call it a terrorist attack,” Patrick Clawson, director of research at the Washington Institute of Near East Policy, told an editorial writer. It calls for a “maximum information campaign and then a maximum diplomatic campaign.”

Diplomacy is indeed the best method to respond to whichever nation or nonstate actor is responsible. But here, too, Trump has made grave mistakes by alienating allies who would be naturally inclined to back the United States. (Many may be hit harder by oil price spikes, too.) Some of this distance can be attributed to Trump abrogating the Iran deal, which is still recognized by European powers, China and Russia — countries that were all party to the accord.

The pact was imperfect, but even the Trump administration acknowledged Iran was in compliance. Now, hit hard by Washington’s “maximum pressure” campaign, Iran is predictably hitting back with provocations like shooting down a U.S. drone, and perhaps with oil-tanker attacks and the Saudi strikes.

Before his bellicose tweet, Trump said he hoped to meet Iran’s president at the U.N. next week (without preconditions, contrary to Trump’s backtracking). But a meeting was nixed by Iran’s Supreme Leader Ali Khamenei.

Trump should keep the offer open while also engaging other world leaders to internationalize the issue. And while the president should indeed work with Saudi Arabia, he should not appear to be led by Crown Prince Mohammed bin Salman, who is in part responsible for the humanitarian disaster in Yemen and likely the killing of journalist Jamal Khashoggi.

Congress would be a more appropriate partner for Trump, especially if a military response is on the table.