John Walsh vows to continue Piers Morgan's Gun-Control campaign on CNN

Walsh will be much more effective at making this argument than Piers for the simple reason that he is much more likable.   From The Wrap:

Besides hosting “America's Most Wanted” and advocating for victims’ rights, Walsh has been a longtime advocate of background checks and other safety measures. He said he would continue that fight now that he is joining CNN as the host of “The Hunt,” a new show about catching fugitives. . . .
“I am the guy that has seen both sides of the issue,” Walsh told reporters Monday. “I own guns. I'm the father of a murdered child. I've done nothing but track violence in America since my son was murdered. We have a serious problem with guns in this country. And we refuse to address it. And the NRA solution to arm every grammar-school 80-year-old teacher with a gun is absolutely ludicrous,” he said.
Walsh said the NRA is so deeply in the pocket of the gun industry that “they're not a lobbyist on Capitol Hill, they're a gun manufacturer rep.” He also said Vice President Joe Biden recently agreed with him that politicians are “scared s—less” of the NRA. . . .

Just because background checks work well in theory doesn't mean that the current system actually works that way.  You can find out some of the problems with the background check system here and here.

Obviously the claim that the NRA wants to arm everyone in schools is a gross exaggeration.  The NRA proposal was to arm uniformed guards, something that Bill Clinton had supported when he was president, and something that I thought was a mistake because armed guards are likely to be the first target.

On polls Walsh says:

“I said to Joe Biden, '90 percent of Americans are for a responsible background check for a gun, and you know what this Congress has done? Not voted on it, not brought it to the floor, not introduced a bill,'” Walsh said. “I said, ‘They're all scared shitless of the NRA, aren't they?'” . . . 

You can find out why his claim is incorrect here.