Opinion writer

The weapons used at the Boston Marathon this week were common pressure cookers — armed with a detonator and filled with BB’s, nails and pellets. The explosions killed at least three people, including an 8-year-old boy, and injured more than 170 others.

Among the weapons used to kill 20 children and six staff members at Sandy Hook Elementary School in December was a .223 Bushmaster rifle. The shooter killed himself with a Glock handgun, after killing his mother earlier that day by firing four bullets into her head.

Eighteen years ago in Oklahoma City, the weapon was a bomb made from a “deadly cocktail of agricultural fertilizer, diesel fuel and other chemicals,” according to the FBI. It killed 168 people, including 19 children. More than 750 people were injured.

A truck bomb containing a 1,336-pound nitrate-hydrogen-gas-enhanced device was used in the 1993 World Trade Center attack. Six people were killed, and more than a thousand were injured.

The weapons deployed on Sept. 11, 2001, were four hijacked passenger jets that crashed into the North and South Towers of the World Trade Center, the Pentagon and a field near Shanksville, Pa. Nearly 3,000 people lost their lives.

This month at Lone Star State College outside Houston, 14 students were wounded in a daytime assault on campus. The weapons? A knife and a scalpel.

And the other weapon used this week was the deadly toxin ricin, found in mail addressed to President Obama and a senator.

The armaments in these high-profile attacks have little in common. Likewise, the motives are all over the lot — or unknown.

Extremist ideologies and anger over the 1993 standoff between the Branch Davidians and the FBI siege of their compound near Waco, Tex., reportedly drove Timothy McVeigh in the Oklahoma City bombing.

Terrorists affiliated with al-Qaeda were responsible for the 1993 World Trade Center attack and the Sept. 11 massacres.

The suspect in the Lone Star State College stabbing spree, 20-year-old Dylan Quick, “had fantasies about stabbing people since the age of 8,” Harris County Sheriff Adrian Garcia said at a news conference. Quick had been planning his attack for a long time, Garcia said.

There still is no official explanation as to why 20-year-old Adam Lanza took his mother’s life and murdered so many innocents at Sandy Hook school this winter. Likewise, we know what was done at the Boston Marathon but not why. So too with the ricin mailings.

While these attacks have no shared theme, they do have a common feature. From Oklahoma City to Boston, the mayhem was the handiwork of individuals. Weapons were the means to produce massive bloodshed. That simple fact needs to be borne in mind.

After horrific events, there is a tendency, perhaps driven by wall-to-wall media coverage, to cast aside everything and issue a call to arms against the latest weapon.

A mass shooting? Go after the guns.

An improvised explosive device? Scour the hills for bomb-making materials.

Aircraft bombing attempted? Ban more than 3.4 ounces of liquid in carry-on luggage.

This isn’t to say that precautions shouldn’t be taken to prevent a recurrence of the sort of tragedy witnessed this week in Boston. Or that steps shouldn’t be taken to keep weapons out of the hands of irrational people. There is, however, a case to be made for broadening our collective perspective.

Message to the postwar generation: There is no returning to the “normalcy” of times past. In the 1950s, the big fears that kept folks squirming in their sleep were of atomic warfare and the polio epidemic.

Today, the forces in our midst are foreign and domestic, organized and lone wolves. Countries from Britain to Israel and Nigeria, sadly, are well familiar. They get it.

Dare I say it? We must get on a different footing here in the United States.

As James R. Clapper, the director of national intelligence, told the Senate Armed Services Committee this week when asked about the Boston attack: Lone wolves, domestic extremists and groups affiliated with terrorists or other extremists are determined to attack.

Security awareness is not the sole concern of law enforcement. It is everybody’s responsibility — at marathons, stadium events, on campus, at cookouts. Threats don’t have to be from a bomb, or an AK-47, or gels on board an airplane.

Am I preaching paranoia? No. Just urging the maintenance of a healthy suspicion.

Because, in 21st-century America, like it or not, this will be the new normal.

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