For three decades, the story of gun control was one of notorious crimes and laws passed in response, beginning with the federal law that followed the assassinations of Robert F. Kennedy and Dr. Martin Luther King Jr. in 1968. Surprisingly, after a Democratic-controlled Congress in 1994 passed bills proposed by President Clinton to restrict certain kinds of assault weapons and to create a national system of background checks for gun purchases, the political pendulum began to swing the other way. President Bush’s defeat of Al Gore in the 2000 presidential election was attributed in part to the perception among gun owners that Mr. Gore was “anti-gun.”
In 2008, the Supreme Court ruled that the Bill of Rights included a guarantee of the personal right to own a gun. The decision was both a measure of how far the pro-gun debate had moved, and a blow to many of the stricter gun control laws adopted by cities like Washington, Chicago and New York.
In recent years, there have been calls for action on gun violence after a series of horrific mass shootings, including the killing of 32 people at Virginia Tech in 2007, the shooting of Representative Gabrielle Gillfards of Arizona and 18 others in 2011, and the deaths of 12 people at a movie theater in Colorado in July 2012. But the bills that were introduced — including ones to restrict sales of 100-bullet magazines or to tighten background checks — went nowhere.
However, in December 2012, the debate was revived again after a gunman carrying semiautomatic weapons forced his way into the Sandy Hook Elementary School in Newtown, Conn., killing 27 people, including 20 young children. Supporters of stricter gun laws gained some hope that the tragedy might be a catalyst for change.
Gun ownership has declined over the past 40 years but almost all the decrease has come from Democrats. By 2010, according to the General Social Survey, the gun ownership rate among adults that identified as Democratic had fallen to 22 percent. But it...