Had officer Chauvin the sense or the pity to take his knee off George Floyd’s neck before killing the man, we wouldn’t have riots and fires and urban warfare this weekend. But that doesn’t make Floyd’s killing the sole cause of this unrest.

To light a fire, you need at least three elements -- fuel, oxygen, and a spark.

The protests and ultimately the riots were ignited by the videos of Chauvin killing Floyd. The oxygen — always present — was America’s history of police violence and racial tension. Some of the fuel, the kindling that made this spark turn into an inferno, was the lockdown of society and the economy amid the coronavirus pandemic.

The lockdowns and the closures and the stay-at-home orders aren’t the only fuel, of course. And the pandemic itself, and the fear of contracting it, must be considered a contributing factor, too.

Yes, we’ve had violence like this America. Yes, police brutality has led to rioting before now. But why didn’t we have downtowns and police stations burnt down after Philando Castille, Tamir Rice, or Eric Garner all died senselessly at police hands? The rioting in Baltimore after Freddy Gray’s death, was mostly limited to Baltimore.

Something bigger is happening now.

Logically, it seems impossible to deny that the lockdowns are a major cause of these once-in-a-generation nationwide protests. As liberal writer and former Baltimore Sun reporter Alec MacGillis put it, “there's been a massive, unprecedented (since 1918) shock to society over the past two months. Of *course* it is shaping what is unfolding now, in a way that didn't happen in, say, 2015-16,” when other police killings happened.

On a basic level, people are more unhappy during this pandemic. Gallup in late April found that “the percentage of U.S. adults who evaluate their lives well enough to be considered ‘thriving’ has dropped to 46.4%, matching the low point measured in November 2008 during the Great Recession.” That’s a 13-point drop from a year ago, so this isn’t about Trump. The share of Americans feeling stress and worry jumped by 50% this Spring.

Unemployment, idleness, and fear will do that. Millions of people are without work. Millions of young people are without school. Everybody’s bars, restaurants, and coffee shops are closed. Cities have removed the rims from basketball courts and threatened fines for getting together with too many of your friends.

Without recreation or work, cut off from friends, and with nothing to do, people will be more on edge. Idleness will also drive people to extreme and unwise actions.

Wesley Lowery, a Washington Post reporter who has covered the beat since Ferguson, wrote that activists and organizers he spoke to in many cities noted “that this enraging death happened at a time when people had been stuck in their homes, cut off from others, and scared for their lives for months.”

Being unemployed, with most of the businesses around you closed down, also makes people poorer. That adds to stress, as well.

In cities, which is where the rioters are concentrated, people — particularly minorities and non-affluent young adults — had to deal with the added hassle of social-distancing and mask-policing. More laws, and more intrusive laws means more potential points of friction between law enforcement and the public, which in turn means more protests, more of which are likely to go south.

Basketball games were broken up. Philadelphia police dragged a man from a bus for not wearing a mask. New York police arrested and handcuffed a mother after she rejected police instructions to wear her mask properly.

For the police, the lockdowns and the virus have added new stresses. The NYPD said that death threats against police rose as they were charged with policing coronavirus rules. With courthouses closed, many police saw all the work they did effectively discarded. Others resented being asked to police petty infractions of new and unclear rules issued by politicians who never intended for full enforcement of those rules.

Finally, when the protestors took to the streets this week, their downtowns already looked like ghost towns.

The anxiety of no school, no pool, no work, no church, and no certainty about the future, combined with added tension with police amid lockdown rules, and suddenly the kindling was a lot dryer, allowing the spark to set off a blaze that is encompassing our whole country.