LAS VEGAS (AP) — After back-to-back mass shootings in Ohio and Texas this summer, gun control burst back on the scene as a major political issue for Democrats. Now it risks taking a back seat as impeachment fever overtakes Washington.

Gun control advocates are determined to prevent that from happening.

Ten White House hopefuls will be in Las Vegas for a forum on gun policy on Wednesday, almost two years to the day after a gunman killed 58 people at a country music festival on the Las Vegas Strip in the deadliest mass shooting in modern American history. The event is being hosted by MSNBC, Marc...