The United States and allies are preparing for a possibly imminent series of limited military strikes against Syria, the first direct U.S. intervention in the two-year civil war, in retaliation for President Bashar al-Assad’s suspected use of chemical weapons against civilians. If you found the above sentence kind of confusing, or aren’t exactly sure why Syria is fighting a civil war, or even where Syria is located, then this is the article for you. What’s happening in Syria is really important, but it can also be confusing and difficult to follow even for those of us glued to it. Here, then, are the most basic answers to your most basic questions.

First, a disclaimer: Syria and its history are really complicated; this is not an exhaustive or definitive account of that entire story, just some background, written so that anyone can understand it.

1. What is Syria?

Syria is a country in the Middle East, along the eastern shore of the Mediterranean Sea. It’s about the same size as Washington state with a population a little over three times as large – 22 million. Syria is very diverse, ethnically and religiously, but most Syrians are ethnic Arab and follow the Sunni branch of Islam. Civilization in Syria goes back thousands of years, but the country as it exists today is very young. Its borders were drawn by European colonial powers in the 1920s. Syria is in the middle of an extremely violent civil war. Fighting between government forces and rebels has killed more 100,000 and created 2 million refugees, half of them children.

2. Why are people in Syria killing each other?

The killing started in April 2011, when peaceful protests inspired by earlier revolutions in Egypt and Tunisia rose up to challenge the dictatorship running the country. The government responded — there is no getting around this — like monsters. First, security forces quietly killed activists. Then they started kidnapping, raping, torturing and killing activists and their family members, including a lot of children, dumping their mutilated bodies by the sides of roads. Then troops began simply opening fire on protests. Eventually, civilians started shooting back. Fighting escalated from there until it was a civil war. Armed civilians organized into rebel groups. The army deployed across the country, shelling and bombing whole neighborhoods and towns, trying to terrorize people into submission. They’ve also allegedly used chemical weapons, which is a big deal for reasons I’ll address below. Volunteers from other countries joined the rebels, either because they wanted freedom and democracy for Syria or, more likely, because they are jihadists who hate Syria’s secular government. The rebels were gaining ground for a while and now it looks like Assad is coming back. There is no end in sight.

3. That’s horrible. But there are protests lots of places. How did it all go so wrong in Syria? And, please, just give me the short version.

That’s a complicated question, and there’s no single, definitive answer. This is the shortest possible version — stay with me, it’s worth it. You might say, broadly speaking, that there are two general theories. Both start with the idea that Syria has been a powder keg waiting to explode for decades and that it was set off, maybe inevitably, by the 2011 protests and especially by the government’s overly harsh crackdown.

Before we dive into the theories, you have to understand that the Syrian government really overreacted when peaceful protests started in mid-2011, slaughtering civilians unapologetically, which was a big part of how things escalated as quickly as they did. Assad learned this from his father. In 1982, Assad’s father and then-dictator Hafez al-Assad responded to a Muslim Brotherhood-led uprising in the city of Hama by leveling entire neighborhoods. He killed thousands of civilians, many of whom had nothing to do with the uprising. But it worked, and it looks like the younger Assad tried to reproduce it. His failure made the descent into chaos much worse.

Okay, now the theories for why Syria spiraled so wildly. The first is what you might call “sectarian re-balancing” or “the Fareed Zakaria case” for why Syria is imploding (he didn’t invent this argument but is a major proponent). Syria has artificial borders that were created by European colonial powers, forcing together an amalgam of diverse religious and ethnic groups. Those powers also tended to promote a minority and rule through it, worsening preexisting sectarian tensions.

Zakaria’s argument is that what we’re seeing in Syria is in some ways the inevitable re-balancing of power along ethnic and religious lines. He compares it to the sectarian bloodbath in Iraq after the United States toppled Saddam Hussein, after which a long-oppressed majority retook power from, and violently punished, the former minority rulers. Most Syrians are Sunni Arabs, but the country is run by members of a minority sect known as Alawites (they’re ethnic Arab but follow a smaller branch of Islam). The Alawite government rules through a repressive dictatorship and gives Alawites special privileges, which makes some Sunnis and other groups hate Alawites in general, which in turn makes Alawites fear that they’ll be slaughtered en masse if Assad loses the war. (There are other minorities as well, such as ethnic Kurds and Christian Arabs; too much to cover in one explainer.) Also, lots of Syrian communities are already organized into ethnic or religious enclaves, which means that community militias are also sectarian militias. That would explain why so much of the killing in Syria has developed along sectarian lines. It would also suggest that there’s not much anyone can do to end the killing because, in Zakaria’s view, this is a painful but unstoppable process of re-balancing power.

The second big theory is a bit simpler: that the Assad regime was not a sustainable enterprise and it’s clawing desperately on its way down. Most countries have some kind of self-sustaining political order, and it looked for a long time like Syria was held together by a cruel and repressive but basically stable dictatorship. But maybe it wasn’t stable; maybe it was built on quicksand. Bashar al-Assad’s father Hafez seized power in a coup in 1970 after two decades of extreme political instability. His government was a product of Cold War meddling and a kind of Arab political identity crisis that was sweeping the region. But he picked the losing sides of both: the Soviet Union was his patron, and he followed a hard-line anti-Western nationalist ideology that’s now mostly defunct. The Cold War is long over, and most of the region long ago made peace with Israel and the United States; the Assad regime’s once-solid ideological and geopolitical identity is hopelessly outdated. But Bashar al-Assad, who took power in 2000 when his father died, never bothered to update it. So when things started going belly-up two years ago, he didn’t have much to fall back on except for his ability to kill people.