Thought Iraq was a blunder? Iran is far worse.

Ivo Daalder, a former U.S. ambassador to NATO, is a senior fellow at Harvard University’s Belfer Center and host of the weekly podcast “World Review with Ivo Daalder.” He writes POLITICO’s From Across the Pond column.

Like many, I used to believe that former U.S. President George W. Bush’s decision to invade Iraq in 2003 was the biggest strategic mistake America had made, at least since the Vietnam War.

That is, until now.

U.S. President Donald Trump’s decision to join Israel in a war against Iran is a far bigger strategic error, and one with far bigger strategic consequences. The reasons for this are many, ranging from the immediate impact on the region and the global economy to the longer-term upshots for Russia and China, as well as the repercussions for U.S. alliances and America’s global standing.

That much is already clear — and we’re only three weeks in.

Let’s start with the similarities: Much like the Iraq War, the war against Iran began based on the presumption that the regime in power would swiftly fall and that a new, more moderate and less antagonistic one would take its place. In both instances, the idea was to remove the greatest destabilizing threat in the Middle East — Saddam Hussein’s regime in the initial case, the theocratic dictatorship in Tehran in the latter — through the swift and decisive use of military force.

But while Bush understood that defeating a regime required ground forces, it seems Trump simply hoped that airpower alone would suffice. As a result, Hussein’s regime fell swiftly — though Bush did vastly underestimate what would be required to rebuild a stable, let alone a democratic, Iraq in its place. But the Iranian government, as U.S. intelligence officials themselves have testified, “appears to be intact” despite Israel killing many of its key political and security leaders through targeted strikes.

Focusing on the region at large, Bush’s misjudgment eventually contributed to a large-scale insurgency, which strengthened Iran’s influence in Iraq and the wider Middle East. In contrast, Trump’s miscalculation has left in place a regime that, aside from assuring its own survival, is now singularly focused on inflicting as much damage on the U.S. and its allies as it possibly can.

Iranian drones and missiles have already attacked Israel and the Gulf states, targeted critical energy production facilities and effectively closed the Strait of Hormuz, which hosts one-fifth of the world’s oil and gas export transits.

Less than a month in, the world is now witnessing the largest oil and gas disruption in history. And as the fighting escalates to include gas and oil production infrastructure, the global economic consequences will be felt by every single country for months, if not years, to come — even if the conflict were to end soon.

The damage that has already been inflicted on the global economy is far greater than the economic consequences of the Iraq War in its entirety.

But that’s not all. Geopolitically, the U.S.-Israel war with Iran will also have far greater reverberations than the war in Iraq ever did.

For one, the Bush administration spent a lot of time and effort trying to get allies on board to participate in and support the war. It didn’t fully succeed in this, as key allies like Germany and France continued opposing the war. But it tried.

Trump, by contrast, didn’t even try to get America’s most important allies on board. Not only that, he even failed to inform them of his decision. And yet, when Iran responded predictably by closing the Strait of Hormuz, the U.S. president then demanded allies send their navies to escort tankers — despite the U.S. Navy so far refusing to do so.

And while it’s true that Iraq left many U.S. allies — even those that joined the war, like the U.K. — deeply scarred, Iran has convinced U.S. allies they can no longer rely on the U.S., and that Washington is now a real threat to their economic security.

That, too, will have a lasting impact well beyond anything the war in Iraq did.

Finally, the fact remains that when Bush decided to invade Iraq, Russia and China were still minor global powers. Russian President Vladimir Putin was only just starting his effort to stabilize the economy and rebuild Russia’s military power, while China had just joined the World Trade Organization and was still a decade or more away from becoming an economic superpower. In other words, America’s blunder in Iraq occurred at a time when the strategic consequences for the global balance of power were still manageable.

Trump’s Iran debacle is occurring at a time when China is effectively competing with the U.S. for global power and influence, and Russia is engaged in the largest military action in Europe since the end of World War II.

Both stand to benefit greatly.

Russia is the short-term winner here. Oil prices are rising, generating more than $150 million per day in extra income for Moscow to feed its war machine. The U.S. is relaxing its sanctions against Russia in a vain attempt to stall prices from ballooning at the pump. All the while, Ukraine is being left to contend with Russia’s missile and drone attacks without the advanced defensive weaponry that’s now being used to protect Israel and the Gulf instead.

China, meanwhile, is watching as the U.S. diverts its military forces from the Indo-Pacific to the Middle East, where they will likely remain for months, if not years. These forces include a carrier strike group, a Terminal High Altitude Area Defense anti-missile system from Korea, and a Marine Expeditionary Force from Japan. And while a disruption in oil and gas supply will be a short-term problem for Beijing too, China’s rapid transition to renewables and close alignment with energy-rich Russia will leave it well placed to confidently confront the future.

Bush and Trump both came to office determined to avoid the mistaken wars of their predecessors. Nevertheless, they both embarked on military adventures fed by a hubristic belief in American power.

But while the U.S. was strong enough — and its adversaries still weak enough — to recoup much of the damage inflicted by Bush’s war, the war unfolding in Iran today will leave behind an America that will have lost much of its global power, standing and influence, destined to confront rising adversaries all on its own.