A gunman murdered nine people in their church in Charleston, South Carolina, last week. He sat among the parishioners as they prayed, then pulled out his gun and shot them dead. This is sadly no longer shocking. Such acts of terrorism, designed to make us feel fearful and powerless, have become familiar.

What has also become familiar is the specific set of weak rationalizations that are uttered in defense and glorification of the gun.

These excuses are offered in response to reasonable discussions to make our communities safer by strengthening the laws, and their enforcement, that govern acquiring firearms. A background check is not needed to purchase a gun from a private seller, or to receive one as a gift, under federal law. It should be.

The excuses:

1) Guns don’t kill people, people kill people.

Guns don’t fire themselves, but they allow shooters to kill many more people, more quickly. They are lethally efficient, on purpose. Guns were used in 77 percent of mass killings since 2006, according to a USA Today analysis of FBI, local law enforcement records and media reports.

2) If one of the victims had only had a gun, they wouldn’t have been killed.

Blaming the victims for their own murder is offensive, and the myth of the “good shooter” doesn’t hold up.

The gun lobby likes to claim that firearms are frequently used in self-defense — as an NRA official has already done in reference to Charleston — but facts don’t bear it out.

According to the Violence Policy Center, only 0.8 percent of intended victims of attempted or completed violent crime used a firearm against an attacker from 2007-11. Most people yelled, ran, made threats without a weapon or offer no resistance.

This excuse is also predicated on the idea that the shooter will be a stranger, and that your guard will be up.

Instead, nationally, 52 percent of mass shooting deaths involved the shooter killing his own family members.

In total, 57 percent of all mass killing victims knew their assailant.

Breakups, estrangement and escalating arguments are among the most common triggers for the violence, according to the USA Today analysis.

3) Mass shootings are terrible but infrequent and we shouldn’t base our gun laws on something rare.

A mass killing, which the FBI defines as the killing of four or more people, happens about once every two weeks in the U.S.

There have been more than 200 mass killings since 2006, and public mass shootings account for one in six of those deaths, according to the USA Today study.

In Arizona, 45 people have been killed in mass shootings since 2006. All but three cases involved family, including one in May in which a Tucson man shot and killed four relatives and then himself.

The month before, a family business dispute in Phoenix ended with a man shooting to death his mother, two brothers and sister-in-law before committing suicide.

The list goes on.

But the venue for murder isn’t the salient point — it’s that ready access to guns, made easier by the fact that few states, and Arizona is not one of them, require a background check for every gun sale or transfer of ownership. Several states have passed laws requiring this, and it’s a common-sense decision.

The refusal of elected officials to put the safety of people ahead of nearly unfettered access to deadly weapons makes our streets, and our homes, more dangerous.