There is a serious dispute among the Republican presidential candidates on one of the most important foreign policy issues facing America. Ted Cruz and Donald Trump want the United States to join with Russia and Iran in backing Syrian dictator Bashar Al Assad as a necessary policy to fight the ISIS terrorist group. Marco Rubio is willing to use U.S. military forces to defeat ISIS and set up a no-fly zone over the non-Assad controlled regions of Syria, thereby containing Assad and putting a check to the expansion of the power of the Kremlin-Iran alliance across the Middle East.

In this dispute, Rubio is right, and Cruz and Trump are dead wrong.

In the first place, the Assad-Kremlin-Iran alliance is not a useful partner in fighting ISIS. On the contrary, as many astute analysts have noted, for example here, and here, there is plenty of evidence that Assad has been deeply involved in creating and supporting the ISIS group. These actions include releasing most of the ISIS leadership from his jails in 2011, providing the group with funds by purchasing its oil, and providing the terrorists with direct tactical air support for their attacks on the Free Syrian Army and other elements of the regime’s real opposition. Assad’s game plan in doing this is simple. By building up the deliberately-horrifying ISIS and helping it wipe out the Western-backed rebels, Assad hopes to present the world with a choice of just two alternatives: ISIS or himself.

The Kremlin is also not a suitable ally against ISIS. On October 31, an airliner carrying over 200 Russians was brought down by a bomb, supposedly planted onboard by ISIS. In response, Russia has sent troops and squadrons of aircraft to Syria for the stated purpose of retaliation. Yet very few of Putin’s blows have been directed against ISIS. Instead, his aircraft, like of Assad, have been raining destruction on Syrian civilians in regions far removed from ISIS control.

This discrepancy, which has been noted sharply noted by many observers, raises some very serious questions regarding the Kremlin’s actions and true intentions. Who really planted the bomb on the Russian airliner? If it was really ISIS, the Russians would be tearing them to pieces right now. But they are not. Why not? Is it possible that the bomb was planted by the FSB to provide a pretext for sending Russian armed forces into Syria?

Suggesting that the FSB might be behind the murder of over 200 Russians may seem outrageous to some people. Such people are extremely naive. In fact, the FSB is an organization which, under other names, such as NKVD and KGB, has murdered millions of Russians within living memory. Moreover, it was Putin’s FSB which, posing as Chechens, detonated bombs in Moscow and other cities in 1999, killing over 300 Russians to provide the terror necessary to justify the dictator’s seizure of absolute power. There is no question about this: After a string of these bombings in Moscow, Russian cops on the beat in Ryazan actually caught FSB agents in the act of planting another bomb in an apartment building. For those who want further details, former FSB agent Alexander Litvinenko wrote an entire book, Blowing Up Russia, laying out the entire operation, for which he was subsequently murdered in London by FSB agents using signature polonium poison -- as a British court recently reconfirmed.

So Putin and his FSB unquestionably have the character and track record to support the suspicion that they might be responsible for placing a bomb on the Russian airliner. But whether or not they did the bombing, they certainly have taken advantage of it to step up their game in Syria.

So what is the Putin gang really up to in Syria? They certainly want to save the Assad regime, and with it, their key naval base in the Mediterranean. But in fact, they are playing for much higher stakes. To understand that, it is necessary to take a step back and look at their global strategic objectives.

Now that they have beaten off the threat of democracy in Russia, the Kremlinites are on the offensive to retake all that they lost in the Cold War, and more. Their strategic doctrine, known as Eurasianism, holds that to resist the encroaching threat of Western liberalism posed by the Atlantic maritime powers, the Eurasian heartland must be united under a new Moscow-led totalitarian synthesis. As Vladimir Putin put it during a four-hour TV extravaganza broadcast promoting his April 2014 invasion of Ukraine, the goal is to create “one Eurasia, from Lisbon to Vladivostok.”

In Syria, Putin is aggressively moving this agenda forward by helping his client Assad bomb and gas hundreds of thousands of Syrians to death, and millions into exile. In 2012, General David Petraeus warned President Obama that this activity, if not stopped, would create a “geopolitical Chernobyl,” and he was right. Over a million of these refugees have been stampeded to Europe, where their arrival is stoking the political fortunes of a host of national socialist parties strongly allied to Moscow. Some American conservatives have cheered the growth of these parties. They should not. The conceptual spectrum of “Left” and “Right” have little utility in understanding this phenomenon; red and black can readily serve as alternative costumes for similar actors. Designations of “East” and “West” would be more useful, with the East end of the spectrum tending towards tyranny and the West toward freedom.

As designed by its chief ideologist, Aleksandr Dugin, Eurasianist ideology embraces all the main anti-liberal movements, including communism, fascism, ecologism, and traditionalism. The perplexed might ask: What do all these apparently disparate enemies of freedom have in common? The answer is simple: They are all enemies of freedom. The continental European ultranationalists are not conservatives in the Anglo-American sense, because they are radical opponents of individual liberty. They are thus firmly in Dugin’s camp of the East, not the West.

As the parties of the European center have no idea of how to handle the situation, the Kremlin’s tribalists are on the march, and not only the European Union, but even the unity of individual European nations is starting to become unglued. This is a key element of Putin’s plan. Once Europe is shattered, with some pieces under Quisling leadership, the whole squabbling assortment will be easy prey for Kremlin domination.

A second element is how the victory of the Iran-client Assad regime would affect the Middle East itself. The Eurasianist plan requires bringing in the Mideast into the fold under the domination of a revived Persian empire, which will join with Moscow as a junior partner in the anti-Western continental block. With the acquiescence of the Obama administration, which has removed the obstacles posed by the presence of U.S. troops in Iraq and Afghanistan, and which will shortly be providing hundreds to billions to dollars in funds to help things along, Iran is taking advantage of the situation to establish its control over a swatch of territory stretching from Lebanon to the Hindu Kush. With its geopolitical position thus strengthened, Iran will then be able to accelerate the development of its nuclear arsenal without threat of effective outside interference. The menace that this poses to the United States and its allies is beyond calculation.

As noted, President Obama, heedless of the warning of his wisest advisor (whom he chose to persecute instead), has been a willing collaborator in this unfolding disaster. It is also understandable that a radical leftist like Bernie Sanders, or a Putin admirer like Donald Trump, should support such a policy. But one would have hoped for better from Ted Cruz.

ISIS is a criminal terrorist entity that needs to be wiped out. But this can’t be done by supporting those who are profiting by its existence. Furthermore, the idea that we need Assad’s legions in order to defeat ISIS is categorically absurd. ISIS has about 40,000 men under arms, which is about the same as the Taliban had in 2001. In Operation Enduring Freedom, the Bush administration eliminated the Taliban state in 60 days (operations began October 7, 2001, the last Taliban city fell December 7, 2001). This was done by providing arms, advisors, and massive tactical air support to the Northern Alliance to roll back the Taliban, with judicious use of American airmobile forces (less than 10,000 were involved) to encircle the Taliban from behind whenever they took a stand. The same tactics (with the Kurds playing the role of the Northern Alliance) could be used to end the caliphate within a similar time frame, if the American government were inclined to do so.  It is only the studied self-imposed impotence of the Obama administration that has created the impression that we must ask Putin, Iran and Assad to bring order to the Middle East -- and thus accept the order that they choose to bring.

As a result of Obama administration fecklessness, the Russians are now in Syria, making removal of Assad nearly impossible. But we don’t need to back Assad’s genocidal consolidation of the new Iranian empire, or help him flood Europe with a million more refugees to destabilize the continent for Moscow. What we need to do is give full support to our own allies to help them wipe out ISIS, seize its territory, and declare a no-fly zone over all the land outside of Assad control, thereby providing security for the people and a basis for the partition and stabilization of the country. This is the sort of policy that Rubio is advocating, and he is right. Nothing less than the Atlantic Alliance, and with it, the Pax Americana, are at stake.

We don’t need Assad to defeat ISIS, and Trump and Cruz are horribly wrong to suggest that we do. We can’t use Assad to defeat ISIS, and Trump and Cruz are horribly wrong to suggest that we can. America needs to lead our allies from the front, not follow our enemies from behind.

Robert Zubrin is president of Pioneer Energy of Lakewood, Colo., and the author of Energy Victory. The paperback edition of his latest book, Merchants of Despair: Radical Environmentalists, Criminal Pseudo-Scientists, and the Fatal Cult of Antihumanism, was recently published by Encounter Books.