Reprinted with permission from TomDispatch.

What if the U.S. had not invaded Iraq in 2003? How would things be different in the Middle East today? Was Iraq, in the words of presidential candidate Bernie Sanders, the "worst foreign policy blunder" in American history? Let's take a big-picture tour of the Middle East and try to answer those questions. But first, a request: after each paragraph that follows, could you make sure to add the question "What could possibly go wrong?"

Let the History Begin

In March 2003, when the Bush administration launched its invasion of Iraq, the region, though simmering as ever, looked like this: Libya was stable, ruled by the same strongman for 42 years; in Egypt, Hosni Mubarak had been in power since 1983; Syria had been run by the Assad family since 1971; Saddam Hussein had essentially been in charge of Iraq since 1969, formally becoming president in 1979; the Turks and Kurds had an uneasy but functional ceasefire; and Yemen was quiet enough, other than the terror attack on the USS Cole in 2000. Relations between the U.S. and most of these nations were so warm that Washington was routinely rendering "terrorists" to their dungeons for some outsourced torture.

Soon after March 2003, when U.S. troops invaded Iraq, neighboring Iran faced two American armies at the peak of their strength. To the east, the U.S. military had effectively destroyed the Taliban and significantly weakened al-Qaeda, both enemies of Iran, but had replaced them as an occupying force. To the west, Iran's decades-old enemy, Saddam, was gone, but similarly replaced by another massive occupying force. From this position of weakness, Iran's leaders, no doubt terrified that the Americans would pour across its borders, sought real diplomatic rapprochement with Washington for the first time since 1979. The Iranian efforts were rebuffed by the Bush administration.

The Precipitating Event

Nailing down causation is a tricky thing. But like the June 1914 assassination of Archduke Franz Ferdinand that kicked off the Great War, the one to end all others, America's 2003 invasion was what novelists refer to as "the precipitating event," the thing that may not actively cause every plot twist to come, but that certainly sets them in motion.

There hadn't been such an upset in the balance of power in the Middle East since, well, World War I, when Great Britain and France secretly reached the Sykes-Picot Agreement, which, among other things, divided up most of the Arab lands that had been under the rule of the Ottoman Empire. Because the national boundaries created then did not respect on-the-ground tribal, political, ethnic, and religious realities, they could be said to have set the stage for much that was to come.

Now, fast forward to 2003, as the Middle East we had come to know began to unravel. Those U.S. troops had rolled into Baghdad only to find themselves standing there, slack-jawed, gazing at the chaos. Now, fast forward one more time to 2015 and let the grand tour of the unraveling begin!

The Sick Men of the Middle East: It's easy enough to hustle through three countries in the region in various states of decay before heading into the heart of the chaos: Libya is a failed state, bleeding mayhem into northern Africa; Egypt failed its Arab Spring test and relies on the United States to support its anti-democratic (as well as anti-Islamic fundamentalist) militarized government; and Yemen is a disastrously failed state, now the scene of a proxy war between U.S.-backed Saudi Arabia and Iranian-backed Houthi rebels (with a thriving al-Qaeda outfit and a small but growing arm of the Islamic State [ISIS] thrown into the bargain).

Iraq: Obama is now the fourth American president in a row to have ordered the bombing of Iraq and his successor will almost certainly be the fifth. If ever a post-Vietnam American adventure deserved to inherit the moniker of quagmire, Iraq is it.

And here's the saddest part of the tale: the forces loosed there in 2003 have yet to reach their natural end point. Your money should be on the Shias, but imagining that there is only one Shia horse to bet on means missing just how broad the field really is. What passes for a Shia "government" in Baghdad today is a collection of interest groups, each with its own militia. Having replaced the old strongman prime minister, Nouri al-Maliki, with a weak one, Haider al-Abadi, and with ISIS chased from the gates of Baghdad, each Shia faction is now free to jockey for position. The full impact of the cleaving of Iraq has yet to be felt. At some point expect a civil war inside a civil war.

Iran: If there is any unifying authority left in Iraq, it is Iran. After the initial 2003 blitzkrieg, the Bush administration's version of neocolonial management in Iraq resulted in the rise of Sunni insurgents, Shia militias, and an influx of determined foreign fighters. Tehran rushed into the power vacuum, and, in 2011, in an agreement brokered by the departing Bush administration and carried out by President Obama, the Americans ran for the exits. The Iranians stayed. Now, they have entered an odd-couple marriage with the U.S. against what Washington pretends is a common foe -- ISIS -- but which the Iranians and their allies in Baghdad see as a war against the Sunnis in general. At this point, Washington has all but ceded Iraq to the new Persian Empire; everyone is just waiting for the paperwork to clear.

The Iranians continue to meddle in Syria as well, supporting Bashar al-Assad. Under Russian air cover, Iran is increasing its troop presence there, too. According to a recent report, Tehran is sending 2,000 troops to Syria, along with 5,000 Iraqi and Afghan Shia fighters. Perhaps they're already calling it "the Surge" in Farsi.

The Kurds: The idea of creating a "Kurdistan" was crossed off the post-World War I "to do" list. The 1920 Treaty of Sèvres at first left an opening for a referendum on whether the Kurds wanted to remain part of what remained of the Ottoman Empire or become independent. Problem one: the referendum did not include plans for the Kurds in what became Syria and Iraq. Problem two: the referendum never happened, a victim of the so-called Turkish War of Independence. The result: some 20 million angry Kurds scattered across parts of modern Iran, Iraq, Turkey, and Syria.