Democratic Sen. Joe Donnelly says he supports background checks for gun buyers, including those who purchase firearms at gun shows.
Donnelly tells The Journal Gazette the checks are needed to keep criminals and the mentally ill from getting weapons "that can cause so much destruction."
Federal law currently requires criminal background checks on prospective customers of federally licensed gun dealers, but it exempts private sellers, including weapons sold at gun shows.
Donnelly had said in January that was receptive to background checks but declined at that time to say whether gun shows should be included.
Indiana is one of 13 states where TV advertisements backed by New York City Mayor Michael Bloomberg are urging viewers to tell their congressmen to vote in favor of comprehensive background checks.