The Crime Prevention Research Center found the worst 5 percent of counties, with 46 percent of the population, accounted for 71 percent of 2024 murders, a share near 71 percent since 2010. Those same high-murder counties, mostly won by Joe Biden in 2020 and Kamala Harris in 2024, also produced 43 percent of firearm murders in the worst 1 percent. Los Angeles advanced a 40-point gun-control plan including checks, registration and bans while Gavin Newsom signed over 80 such measures and Pennsylvania Democrats seek similar laws after November.