Taking the oil is the most dangerous and irresponsible of all of the Republican nominee’s policy proposals, writes Bruce Riedel. It’s one he has repeated often. If you want permanent war in the Middle East and a titanic clash of cultures between Islam and America, he writes, it’s your best bet. This piece originally appeared in The Daily Beast .

Republican Party presidential nominee Donald Trump has said repeatedly the United States should take Iraq’s oil as the spoils of war. With him, it’s an old refrain that goes back at least five years.

But Trump never says what “taking the oil” of Iraq really means: an endless occupation army in the Persian Gulf surrounded by enemies, without allies, and isolated hopelessly from the Islamic world. It would have to be an open-ended occupation, which would polarize America more than ever. It would reinvigorate the global jihad, and it would disgrace our fundamental values as a nation.

There have been several foreign policy debacles over the last 15 years, but with this the Republican Party would own the greatest foreign policy disaster in American history.

Iraq’s oil is distributed across the country with deposits in the north and south, but the largest quantity is in the south in and around Basra province. Since Trump says he opposed the Iraq war he would not want to take all of Iraq. So the less costly approach would be to seize Basra and the oil infrastructure around it. Last week he said he would “leave a certain group behind” to hold the oil wealth for America. That group would have to be the United States military.

Obviously Iraqis will resist the loss and indefinite occupation of the most lucrative part of their country so a permanent American military presence will be necessary in Basra. How large that presence would be would depend on how much resistance it faced.

Since Basra province has over 2.5 million people, almost all Shiite Arabs, their resistance alone would be challenging. But they would not be alone. The Shiite-dominated government in Baghdad would support its citizens, adding to the struggle. It will turn attention away from fighting for Mosul, and focus on recovering Basra.

It will be a grueling war. The city of Basra, the provincial capital, is the hottest place on earth and this summer posted the all-time highest temperature on the planet.

Basra sits immediately next to Iran, which controls the eastern side of the Shatt al Arab waterway, which is Iraq’s only outlet to the sea. Tehran would certainly back the Shiite resistance in Basra, as it did when the British occupied the province after the 2003 invasion. For the British army it was a painful, expensive, and thankless mission.

Iran might be careful to avoid provoking all-out war with Trump by a too-overt backing of the resistance, but it would be well positioned to cause constant frictions and difficulties for the occupation forces and for oil extraction. Iran’s own oil is next door in its Khuzistan province. Iran fought an eight-year war to prevent Saddam Hussein from taking its oil. It would certainly revisit its decision to put off getting the bomb.

To escape the narrow bottleneck of Iraq’s access to the sea, Trump could expand the oil takeover further south into Kuwait. After all, we liberated Kuwait from Saddam Hussein a quarter-century ago. By Trump’s logic, why not take their oil (and their country) as overdue spoils of war?

That would unite the Arab and Muslim world against America, if the takeover of Basra had not already done so.

Taking Kuwait adds another 3 million people to the occupied zone. It also adds a lot more oil and a major port on the Gulf. The U.S. already has a sizable military presence in Kuwait that could form the nucleus of the occupation force. But many more would be needed.

All the oil-exporting countries of the region would oppose the takeover since they’d obviously be thinking they might be next. They could embargo oil exports to create a global oil crisis, but that would hurt Europe, China and India more than America. They would complain to the United Nations but the veto would make that a useless gesture.

They could support resistance to the American occupation. Trump could then just take more oil. Saudi Arabia’s Eastern Province and Qatar would be obvious targets. A large takeover like this would give Washington control of the global energy system. It would also mean more territory and people under an occupation force numbering into the many hundreds of thousands of American men and women.

Trump started talking this way long before the so-called Islamic State threatened the region or the United States, but now he says he’d take it as part of the fight against ISIS.

In fact, America “taking the oil” would destroy immediately the coalition fighting the Islamic State and eviscerate the struggle against al-Qaida as well. Both terrorist groups would argue they had been right all along: America only wanted Islam’s oil. The two rivals might reunite. Recruitment of extremist fighters would skyrocket.

Recruitment of extremist fighters would skyrocket.

No Muslim state would host American troops or cooperate with counter-terrorist operations. Friendly Arab governments like Jordan would have to break ties with Washington or face massive unrest. Americans traveling in the Islamic world from Morocco to Indonesia would be at risk. Sunnis and Shiites alike would stalk Americans.

None of our Western allies would support taking the oil. (Canada would have to wonder if Alberta is next.) The Europeans would see such a naked land grab as a return to the era of Hitler and Stalin.

Russia, on the other hand, would claim its seizure of Crimea was post facto legitimized. Trump and Vladimir Putin would be fellow war criminals. China would be tempted to go for more influence in the South China Sea. The growing American-Indian rapprochement would be endangered, if not broken completely.

Pakistan would redouble its efforts to build more nuclear weapons to prevent a fate like Iraq. The Saudis would offer Islamabad a fortune for the bomb. Pakistan’s generals would be tempted.

In short, the world order based on the principle that seizing territory by force of arms is inadmissible would collapse. The world order fashioned by generations of American leaders from both parties would be threatened as never before by our own country.

This is not the first time the idea of taking the Arabs’ oil has surfaced in the U.S. In 1973-1974, after Saudi Arabia’s King Faisal imposed an oil embargo on America for supporting Israel in the 1973 war, the idea of seizing the kingdom’s oil fields was openly discussed in the nation’s foreign policy think tanks. If President Richard Nixon had ordered a takeover, Faisal undoubtedly would have called for a jihad to defend Islam’s birthplace. His brother King Salman would do the same today.

Taking the oil is the most dangerous and irresponsible of all of the Republican nominee’s policy proposals. It’s one he has repeated often. If you want permanent war in the Middle East and a titanic clash of cultures between Islam and America, it’s your best bet.