When a mass murderer shoots a group of Americans — which has happened 143 times since January 20, 2009 — President Obama often offers a by-now familiar response: We're shocked. We grieve. We pray. Again. 

The first time there was an incident where four or more people were killed by gunfire under Obama occurred one week after he took office. The most deadly was the murder of 26 children and staffers at Sandy Hook Elementary in December 2012. There have been such killings in the heavy majority of states since 2006.

A man in Binghamton, New York entered an immigration center in April 2009, and began shooting. He killed 13 people, having blocked the back entrance with his car. It appears to be the first time Obama was compelled to offer a public response, and it was a brief one. "Michelle and I were shocked and deeply saddened to learn about the act of senseless violence in Binghamton, New York today. Our thoughts and prayers go out to the victims, their families and the people of Binghamton." Subsequent comments include the same components: He and / or he and Michelle are shocked and saddened. His heart goes out to victims; our hearts are broken.

In January 2011, Rep. Gabby Giffords was shot in the head in Tucson, Arizona. Obama flew to Tucson and participated in a memorial service in an arena at the University of Arizona. He let his natural inclination toward oration take over. He spoke about Christina Taylor Green, who died of gunshot wounds in a supermarket parking lot at the age of 9.

As has already been mentioned, Christina was given to us on September 11th, 2001, one of 50 babies born that day to be pictured in a book called Faces of Hope. On either side of her photo in that book were simple wishes for a child's life. "I hope you help those in need," read one. "I hope you know all the words to the National Anthem and sing it with your hand over your heart." "I hope you jump in rain puddles."

If there are rain puddles in Heaven, Christina is jumping in them today. And here on this Earth — here on this Earth, we place our hands over our hearts, and we commit ourselves as Americans to forging a country that is forever worthy of her gentle, happy spirit.

Obama learned about the 2012 shooting at movie theater in Aurora, Colorado shortly before a campaign event. Obama's desire to rein in gun violence was already obvious. "I’d like us to pause in a moment of silence for the victims of this terrible tragedy," he said to an audience of supporters there to hear a very different speech, "for the people who knew them and loved them, for those who are still struggling to recover, and for all the victims of less publicized acts of violence that plague our communities every single day." There was a moment of silence, as there was in Arizona.

When a man entered the Navy Yard in Washington, DC last year and attacked workers with a shotgun, Obama's tone was different: he was the commander in chief, reacting to an attack on his armed forces. "These are men and women who were going to work, doing their job, protecting all of us. They’re patriots, and they know the dangers of serving abroad — but today, they faced unimaginable violence that they wouldn't have expected here at home," he said then. That's similar to what he said in the wake of the shooting at Texas' Fort Hood in November 2009 that killed 13 people — the first time Obama read off the names of victims. And it's similar to what he said on Wednesday, after four people died in the most recent attack there.

Any shooting is troubling. … We know these families. We know their incredible service to our country and the sacrifices that they make. Obviously our thoughts and prayers were — are with the entire community. And we are going to do everything we can to make sure that the community at Fort Hood has what it needs to deal with the current situation, but also any potential aftermath.

That last bit was a rare appearance of politics; Obama has been criticized for not providing enough support to victims of the 2009 shooting.

By the time the Newtown massacre happened, Obama was an old hand at these speeches. But the scale of the attack and age of the victims made the moment, and his response, much more significant. "Here in Newtown, I come to offer the love and prayers of a nation," he said at a prayer service held in the town. "I am very mindful that mere words cannot match the depths of your sorrow, nor can they heal your wounded hearts." He offered condolences, identified the dead children by name. "Charlotte. Daniel. Olivia. Josephine. Ana. Dylan. Madeleine. Catherine. Chase. Jesse. James. Grace. Emilie. Jack. Noah. Caroline. Jessica. Benjamin. Avielle. Allison." And he made a call to action that went unheard the next Spring: "We’re not doing enough" about gun violence, he said. "And we will have to change."

Since then, he's given multiple other statements following mass shootings. Our hearts are broken. We grieve. Again.

READ OBAMA'S STATEMENTS: