Last night, at an otherwise peaceful protest march in Dallas over recent police shootings, someone opened fire on law enforcement, killing five officers and wounding six. In what appears to have been a carefully planned ambush, at least one gunman had strategically positioned himself as a sniper at a high point surrounding the protest route. According to Dallas officials, some of the officers had been shot in the back.

One suspected gunman has been killed. He has been identified as Micah Xavier Johnson, 25, of Mesquite, Texas. His motive was apparently racial revenge for the recent deaths of black men at the hands of police officers.

Three others have been arrested in connection with the case, although it is unclear whether they are suspected of participating in the actual shooting.  Whatever the details prove to be, we know it was the deadliest day for American law enforcement since the attacks of Sept. 11, 2001.

As of this morning, the identity of only one of the fallen had been released. He is Brent Thompson, 43, a Dallas Rapid Transit Authority officer.

Later in the day, Dallas police officials released the names of the remaining dead: They are Lorne Ahrens, Michael Krol, Michael J. Smith and Patrick Zamarripa.

It's hard to wrap your head and your heart around something like this. The murdered police officers were just doing their duty, protecting their community. The Dallas police department has also been lauded nationally for the progress it has made in reducing violent encounters and brutality complaints.

As one protester described last night's scene to the Dallas Morning News, "The cops were peaceful. They were taking pictures with us and everything." Here's a photograph tweeted out by the Dallas Police Department, roughly 45 minutes before the first shots rang out:

"This was peaceful. This was peaceful," another protester said. "We were headed back to our cars to go home. But we turned that corner [at Main Street] and all hell broke loose."

Last night gave us another grim reminder of where the concept of "an eye for an eye" justice will take us -- we can now count five innocent victims of that line of thinking. As Dr. Martin Luther King Jr. reminded us, an eye for an eye leaves everybody blind. But still, at times such as this, with emotions high, it is easy to forget our better natures and call upon the darkness. The temptation is there.

For example, last night former U.S. Rep. Joe Walsh, now an Illinois talk-radio host, tweeted and then deleted the following:

And here in Georgia, somebody in a passing car took potshots at a police officer in Roswell early this morning. A suspect has been arrested. That's the kind of stupidity that a tragedy like this can engender. That's the kind of deeply irresponsible rhetoric and action that can turn an already terrible situation into something much, much worse. Don't go there, America. We are better than this. We are we; we are not them and us.

It's also important to make it clear that the killers in Dallas are no more representative of those protesting than the likes of Michael Slager, the South Carolina policeman who gunned down a fleeing man in cold blood last year, is representative of decent law enforcement officers who put their lives on their line every day. Peaceful protest is an honorable tradition of public debate in a democracy that must be sustained. It is not an act of violence, it is a repudiation of violence.

Shooting down police officers in cold blood has absolutely nothing to do with peaceful protest. It is an act of terror, perpetrated not just against those in uniform but against all of us, of every race, creed, age and gender. We grieve for Dallas, for the families and colleagues of those killed last night in the line of duty, and for those around the country who put on the badge and uniform this morning with heavy hearts and a worried mind.

----------

UPDATE at 12:00 p.m.:

In a statement released earlier today, Gov. Nathan Deal announced that flags at state offices would fly at half mast to mourn "

The flag decision is of course appropriate. However, what happened in Dallas was not an "anti-police" protest, it was an "anti-police brutality" protest. The distinction is crucial, because it cuts to the core of what this is about. An "anti-police protest" is a protest against all police officers, and to describe the Dallas march that way is to willfully distort its message and intention.

As I note above, the Dallas march, like those in Atlanta and elsewhere, was intended to protest the actions of a few. It is no more accurate to call it "anti-police" than it would be to call police officers in general "anti-black" based on the actions of a few isolated individual officers.

The snipers did not recognize that kind of distinction, treating everyone in a police uniform as a target. That's why the rest of us must be better than that. Deal should clarify and reissue his statement.

-------------------

UPDATE at 1:20 p.m.: Gov. Deal has indeed clarified and reissued that statement.

"The anti-police incident to which I referred was the shooting of law enforcement officers, as that was the stated intent of the shooters," he said on Twitter. "It was not in reference to those peacefully demonstrating. Again, my thoughts and prayers are with all those who’ve suffered loss of a loved one this week."

That last sentence is important, extending condolences to those lost in Minnesota and Louisiana as well as in Dallas.