Who is crazier? The gunman, or those who let him buy an AR-15 rifle?

A senior at Marjory Stoneman Douglas High School weeps in front of a cross and Star of David for shooting victim Meadow Pollack while a fellow classmate consoles her at a memorial by the school in Parkland, Florida, U.S. February 18, 2018. REUTERS/Jonathan Drake

President Trump said that the shooter who slaughtered 17 people at a South Florida school was “mentally deranged.” That’s possibly true, but the millions who keep voting for legislators who defend virtually unrestricted sales of semi-automatic weapons are also responsible for the insanity of America’s mass shootings.

The Republican majority in the U.S. Congress has been so supportive of virtually unrestricted gun sales — even for people with serious mental health problems — that the Senate in 2016 voted down a bill to prohibit gun sales to people who are on the U.S. terrorism watch list. A potential terrorist cannot board an airplane in this country, but can buy a semi-automatic rifle.

Here are the facts:

— The attack on the Marjory Stoneman Douglas High School in South Florida, was the 30th mass shooting in 2018, according to the Gun Violence Archive. And we are only in February.

A senior at Marjory Stoneman Douglas High School weeps in front of a cross and Star of David for shooting victim Meadow Pollack while a fellow classmate consoles her at a memorial by the school in Parkland, Florida, U.S. February 18, 2018. REUTERS/Jonathan Drake

— There have been more than 1,600 mass shootings since 2012, according to the Gun Violence Archive. Together, these mass shootings resulted in 1,829 people killed and 6,447 wounded.

— The United States has the most privately owned guns in the world. There are 89 guns per 100 people in America, compared with 46 guns in Switzerland, 45 in Finland and 32 in Sweden, according to the 2007 Small Arms Survey.

— Nikolas Cruz, the young man suspected of having perpetrated the Broward County mass shooting with a semi-automatic AR-15 rifle, bought the weapon legally last year when he was only 18. Cruz was not old enough to be allowed to buy a beer, but could legally buy an assault weapon.

— Semi-automatic weapons such as AR-15 rifles are increasingly being used in mass shootings in America. The man who killed 58 people attending a concert in Las Vegas last year, had 23 weapons in his hotel room, including several AR-15 rifles.

— It hasn’t always been like this. Such attacks with assault weapons have increased since 2004, following the expiration of a ban on assault rifles that Congress passed and President Clinton signed in 1994. There were some attempts to renew the ban, but they all failed, largely because of lobbying by the gun industry-supported National Rifle Association (NRA.)

— Congress has not even been willing to pass a law requiring background checks to make sure that gun buyers don’t have a history of mental illness.

— The NRA and its affiliates spent about $50 million to help President Trump and Republicans win the 2016 elections, according to the Center for Responsive Politics and The Hill. Among the top beneficiaries of NRA funds in the last elections was Sen. Marco Rubio, R-Florida, who got $3.1 million, the study said.

Following the latest mass shooting, Trump and most Republicans in Congress followed the usual script after every such incident: They gave their “thoughts and prayers” for the mourning families and said that gun legislation shouldn’t be discussed until after the mourning period.

But, after a few days, national attention will shift to the next crisis, we will forget about the issue and neither Congress nor the president will do anything. We have seen this movie too many times.

A seemingly shaken Rubio told Miami’s NBC-6 after the Parkland shooting, “This is inexplicable.” What is inexplicable is how a clearly disturbed 19-year-old who posed with a gun in social media was legally able to buy a semi-automatic weapon?

Yes, the Constitution says Americans have the right to bear arms, but it doesn’t say they have the right to buy a bazooka. The Constitution also says Americans have a right to free speech, and yet there are libel laws to prevent that right from being misused.

It’s time for Trump and Republicans in Congress show real leadership and allow some gun safety measures, such as mandatory background checks and the prohibition of gun stocks like those used by the Las Vegas shooter. Otherwise, there will be only one way to end this increasingly frequent American tragedy: ousting the Republican majority in Congress in November’s elections.