As mass shootings, including the recent attacks on police officers, have continued to make headlines, public support for gun control has risen. Some state governments have passed tougher gun laws despite opposition to such measures by the National Rifle Association (NRA) and its allies in Congress. At the same time, conservative states such as Texas have enacted laws allowing licensed gun owners to carry guns in public. The gun issue has generated high-profile court cases, including one filed by parents of children killed in the 2012 Sandy Hook Elementary School shooting in Newtown, Conn. The November presidential election looms large in how the issue will be treated in the courts, as it will help determine the makeup of the Supreme Court following this year’s death of conservative Justice Antonin Scalia.

At a vigil in Los Angeles, Alison Cosio holds a photo of her friend Christopher Sanfeliz, one of 49 people killed in a mass shooting at an Orlando, Fla., nightclub in June. (Getty Images/David McNew)

Shootings involving multiple deaths dominate the news. The deadliest mass shooting by a single gunman in U.S. history occurred in June when a man with an assault-type rifle and a handgun opened fire inside a crowded gay nightclub in Orlando, Fla. 1 By the end of a three-hour hostage standoff, police had killed the gunman, 29-year-old Omar Mateen, 49 others were dead and scores of others were wounded. Authorities described Mateen as a “homegrown extremist” who expressed support for various radical Islamic groups. 2 President Obama called the incident “an act of terror and an attack of hate.” 3

The massacre followed a high-profile incident last December in San Bernardino, Calif., when Tashfeen Malik, 29, and Syed Farook, 28, a couple reportedly inspired by the Islamic State terrorist group, shot and killed 14 people at a holiday party before dying in a shootout with police. 4