WASHINGTON — Rep. Eric Swalwell, D-Calif., added a new wrinkle to the gun debate recently with a proposal to force Americans to sell off their so-called assault weapons — or else.

Swalwell says he was inspired to act by the high school shooting in Parkland, Florida, and the surviving students who have since led a nationwide campaign to tighten gun laws. His plan, which he debuted in a USA Today op-ed, is modeled on Australia, which responded to a 1996 mass shooting by forcing gun owners around the country to sell newly prohibited weapons.

But while Australia comes up often in gun debates, almost no prominent figures have proposed national laws that would demand that gun owners turn in existing weapons en masse. Gun safety groups and leading Democrats have rallied around more modest bipartisan measures like expanded background checks and mostly tiptoed around ideas that Second Amendment activists could label "gun confiscation."

Until now, that is. NBC News talked with Swalwell to discuss his plan, its critics, and why he thinks Democrats need to be more aggressive in their thinking on guns. Below is our conversation, edited for length and clarity.

NBC NEWS: Tell me a little about how you came to this idea and why you thought there needed to be a proposal that went further than the existing bills out there now.

Swalwell: It's something I've given a lot of thought to over the last 10 years working as a prosecutor who saw the devastating effects that an assault weapon could do to someone's body, leaving almost little chance of surviving if you are hit.

I told a story in the op-ed about a victim who was shot in the back of the thigh. I remember his family members asking me while I was interviewing them, "How could you die if you're shot in the thigh?" When the pathologist told the jury that the sheer energy from that round was enough to cause the blood loss after hitting an artery, I think they were just stunned that a weapon that is legal in our country could do that kind of damage. Then when you think about the features, a pistol grip which allows you to essentially spray a crowd, we've seen time after time that too many people just don't have a chance.

I thought about the different ways to address it, with a lot of respect for the assault weapons ban that was in place and expired, but once I gave it careful thought and listened to these students I concluded the only way to do this is to get those weapons out of our communities. But while recognizing that people bought them when they were legal and there should be compensation during a grace period ideally to buy them back and then a ban on possession.

I'm not naive about this, I understand this is quite an undertaking. But I don't accept that we have to be so defeatist about it that doing nothing or nibbling around the edges is going to make us safer. I also don't believe you will get every single assault weapon back, but I think you can get a good amount of them back and seriously reduce the number of people killed by them.

How would you define an assault weapon? One common criticism of the original 1994 Assault Weapons Ban is that it was fairly narrow and gun manufacturers were able to sell weapons that offered similar firepower after making relatively small changes.

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I would stick largely to the definition that has been used before, recognizing it would have to evolve as manufacturers try to come up with technical ways around it. I'd make sure we get rid of detachable magazines and the pistol grip — to me that’s the feature that make it most deadly.

You estimate up to 15 million guns would be affected by a ban. How would you enforce that? There are only about 5,000 employees at the Bureau of Alcohol, Tobacco, Firearms and Explosives.

The way I see it is you have a grace period to buy them back. If you do not participate in the buyback, I'm proposing that we would have a way that they could be kept at a licensed shooting range. You could still fire them there, shoot for sport at a licensed range or licensed hunting club, but they would no longer be at a shopping mall, at a church, in a car, but kept securely to protect the most people.

I'm not proposing a roundup or confiscation. It would be like anything else that's banned: If you're caught with it there would be a steep penalty. Any fear of ATF agents going door to door to collect assault weapons is unfounded and not what is proposed here. They don't go collecting drugs that are banned or any other substance or weapon that's banned and I’m not proposing that here.

Jumping off that parallel with drugs, there's a renewed look at our drug laws in recent years and a common argument for scaling them back is that they turn many ordinary nonviolent Americans into criminals. Are you worried about setting up a situation where large numbers of currently law-abiding Americans are suddenly subject to arrest?

I have great faith that most Americans are law-abiding and care about the rule of law and if they're told a weapon is no longer allowed in their community and they would be compensated they would find a way to do the right thing. If somebody doesn't sell it back and doesn't keep it in a secure place then, yeah, they would be subjected to stiff penalties.

Tell me about those stiff penalties. Are we talking about a felony with jail time or more a misdemeanor?

I'd want to first get the gun. I wrote this to start a conversation and I'm open to what those penalties would be and it would be state-by-state driven. I'd say there would be a federal assault weapons ban that would give a federal prosecutor their own ability to enforce it, but whether it's a misdemeanor or felony, I'm more focused on ideas that get the most guns out of the hands of anyone who could do harm to a community.

Are you prepared for some of the confrontations that might erupt from this? You’re surely familiar with the slogan, "I'll give you my gun when you pry it from my cold dead hands."

You know what gives me the courage to do something about this and doesn't make me afraid are these kids. I'd had it backwards this whole time. I've told town hall participants and reporters in the media that we can protect the Second Amendment and also protect people's lives. What these kids have taught us is their right to learn, their right to go home, their right to live is supreme over any other right. We should put that first.

It sounds like you take issue with how Democrats have approached this in the past, which is a more conciliatory strategy where you say, "Of course, I support the Secondment Amendment, but…" and then look to centrist members to find areas of agreement for legislation.

I think (the old) approach has created a false equivalence between the Second Amendment and someone's right to go to the church and go home, someone's right to go to a mall and go home, someone's right to go to a concert and go home. In that false equivalence, we've allowed I think an expansion of harmful weapons being put out in our communities.

That approach isn't bringing us any changes that are protecting us, that approach hasn't gotten us background checks, that approach hasn't gotten us mental health records being reported federally, that approach didn't even stop bump stocks from being administratively approved.

It's also a defensive approach in that nobody is saying the Second Amendment is not important or guns should be taken away. (My approach is) saying that assault weapons aren’t protected by the Second Amendment so it's not even accepting the argument that we're talking about the Second Amendment.

In the past, the NRA and other gun rights groups have really jumped on anyone who's suggested anything that sounds like gun confiscation…

They've used that phrase, they've already accused me of starting a civil war, it's already out to their members and all over social media and conservative news sites. I understand. I was wide-eyed about what the risk would be doing this, but I just am not convinced that there's another way to protect people in our communities from these weapons of war other than taking them off the streets.

What's your plan for what comes next? Is there going to be a specific bill? Have you identified any potential co-sponsors?

I’m going to talk to my colleagues when we get back. There are a lot of issues important right now and this (younger) generation isn't a single-issue generation: They care about health care and climate change and education. But their right to live is pretty important because they’re living in fear right now. The number of high school students who have told me all over this country the panic that sets in when a fire alarm goes off, or when a book drops, is something that no one should have to experience. They're all sitting on the edge of their seats fearing that the next shooter is going to come into their classroom and they're seeing we're doing nothing to protect them.

What I'm hoping to do is start a conversation, to work with my colleagues on this, but to address this boldly and not be resigned to thinking that we're helpless, because we're not helpless. We were sent to Washington to do big things and protect people.