Attacks from abroad — Pearl Harbor, 9/11 — have united us.
Yet domestic atrocities lately seem only to deepen our divisions.
The bombing of the Murrah federal building in Oklahoma City was seized upon to savage government critics like Rush Limbaugh.
After the murder of six innocents, including a 9-year-old girl, and the wounding of Rep. Gabrielle Giffords and a dozen others in Tucson, Ariz., by a certifiable lunatic, Sarah Palin was charged with moral complicity.
The slaughter of 20 first-graders at Sandy Hook Elementary in Newtown, Conn., put the National Rifle Association in the media cross hairs. With the massacres at Columbine, Virginia Tech and Ft. Hood, Tucson and Newtown are now the primary exhibits in the prosecution case for the disarming of America.
Are the gun controllers winning? They have surely made gains.
Maryland, New York, Connecticut and Colorado have outlawed high-capacity magazines used in semiautomatic rifles and pistols. All four have outlawed all versions of the AR-15 rifle used in Newtown. All have imposed background checks on all gun purchasers.
Maryland has gone further. According to The Washington Post, Maryland's law "would force gun buyers to provide fingerprints and undergo classroom training, target practice and background checks to obtain a license to buy a firearm. No state had sought to impose a licensing requirement in nearly 20 years."
To make licensing and fingerprinting a condition of buying a gun seems a prima facie violation of the Second Amendment.
At the federal level, the going has been tougher for the gun controllers. Sens. Joe Manchin of West Virginia and Pat Toomey of Pennsylvania have introduced a bill to require background checks on all gun purchases on the Internet and at gun shows.
Yet Harry Reid has warned that any attempt to outlaw the AR-15, the most popular rifle now selling in America, or limit magazines to 10 rounds might not carry 40 votes, let alone the 60 senators needed to stop a filibuster.
So who is winning this ideological and cultural war?
Measured by media coverage, the gun controllers. Mayor Michael Bloomberg is treated with a deference Wayne LaPierre of the NRA and Larry Pratt of Gun Owners of America will never know.
But measured by wins and losses, LaPierre and Pratt seem to be holding their own.
Polls show support for new gun laws dropping steadily. And there has been an explosion in sales of AR-15s and high-capacity magazines.
Makers of the rifles cannot fill back orders. A number of Americans seem so fearful of new restrictions on their gun rights they are stocking up on weapons and ammunition as though the revolution were at hand.
Going back further, gun sales have soared in recent years. According to CNS News, there have been 70 million FBI background checks for gun purchases since February 2009.
In the last two decades, many states have passed laws allowing citizens to carry concealed weapons and reduced the number of sites where weapons may not be carried.
Gun manufacturers like Beretta in Maryland and Colt in Connecticut are talking about moving to more friendly states.
Another problem the gun controllers seem unable to overcome is the suspicion they are not being honest about their ultimate goal — and that goal is a place far beyond having criminal background checks.
What is behind the suspicion?
How many gun controllers who today profess their love of and loyalty to the Second Amendment spoke out against the new Maryland law that requires fingerprints and licensing?
How many said Gov. Martin O'Malley had gone too far?
How many spoke out against the infamous Washington, D.C., gun law that was overturned by the Supreme Court in the 2007 Heller decision? How many would object to fastening something like that gun law on the entire nation?
Under that law, city residents were forbidden to own handguns, semiautomatics or any unregistered weapon. Only guns registered before 1976 were permitted to private citizens, and guns kept in the home had to be "unloaded, disassembled or bound by a trigger lock or similar device."
Law-abiding citizens were left naked to a criminal class in a city then known as the murder capital of America.
Joe Biden might call gun rights militants the "black helicopter crowd." But if Second Amendment folks fear that outlawing the AR-15s is only the beginning for the Biden crowd, they may be not far off the mark.
One need not be paranoid to get the sense that what gun controllers saw in Newtown was not only an atrocity but an opportunity — to advance toward their ultimate goal of overturning Heller and disarming America.
After all, only one more Obama justice is needed.
How often, for example, have Biden and Obama condemned their Hollywood bundlers for glamorizing automatic weapons in a thousand films that have reaped Hollywood untold billions of dollars?
Has Obama ever called on the Hollywood moguls and actors who have contributed mightily to his campaign, or ex-Sen. Chris Dodd, head of the motion picture association, for restraint in the use of guns in films?