“I am, if it’s a weapon that was designed to kill people on a battlefield,” O’Rourke replied, to applause. He continued, in graphic detail: “If the high-impact, high-velocity round, when it hits your body, shreds everything inside of your body, because it was designed to do that, so that you would bleed to death on a battlefield and not be able to get up and kill one of our soldiers.”

Last month, a gunman killed nearly two dozen people in a Walmart in O’Rourke’s hometown of El Paso. The weapon used in the shooting was a military-style weapon resembling the AK-47. After the attack, O’Rourke stepped away from campaigning, instead spending time in the community. He continued that outreach after killings in Odessa and Midland, Tex., — an attack in which the gunman used an AR-15-style rifle.

“When we see that being used against children,” O’Rourke continued — “and in Odessa, I met the mother of a 15-year-old girl who was shot by an AR-15, and that mother watched her bleed to death over the course of an hour because so many other people were shot by that AR-15 in Odessa and Midland, there weren’t enough ambulances to get to them in time — hell, yes, we’re going to take your AR-15, your AK-47.”

The method for doing so? A mandatory buyback, in which gun owners would have to turn in rifles like those named by O’Rourke but would be compensated for doing so.

In short order, a bit of political conventional wisdom formed: O’Rourke had damaged his own chances of being elected president by staking out a position so distant from the center. What’s more, he had probably harmed the eventual Democratic nominee for president in 2020 (at this point, probably not O’Rourke) by giving President Trump and his allies the ability to claim that Democrats intend to take guns away from the public.

On Friday morning, Trump’s reelection team did exactly that, posting a video on social media calling Democrats a “joke” — because they “will take away your guns.” To illustrate that point, the video depicts a handgun in a no-smoking-style red circle.

Whenever the conventional wisdom settles on something, it’s useful to assume that the opposite might be true. Is it the case, then, that O’Rourke’s position won’t be that problematic politically?

One Texas legislator seemed to summarize the most fervent opposition to O’Rourke’s proposal by tweeting that his “AR is ready for you Robert Francis” — using O’Rourke’s given name. The tweet was removed, given the implications of violence, but it’s worth highlighting in part because it represents the fervor of opposition to such a ban.

But then, the guy who tweeted that is a Texas Republican. Was he likely to back the 2020 Democratic candidate anyway? Are there many people who fervently oppose a buyback of assault weapons who were otherwise on the fence in the presidential contest?

There’s majority support in both polls for legislation that would ban the sale of assault weapons. In our poll, 56 percent of Americans back that idea, about the same as in the NPR poll. That includes at least a third of Republicans and 4 in 10 gun owners or people who live in a household with a gun.

(Philip Bump/The Washington Post)

That’s not the same as the buyback issue, of course. It’s also a policy that was in effect for a decade until 2004.

Both The Post-ABC poll and the one from NPR asked specifically about a proposal like O’Rourke’s. In both polls, views were split. Our poll had a slim majority supporting a mandatory buyback; NPR’s was evenly divided.

(Philip Bump/The Washington Post)

Again, though, note that there’s more support from Republicans and gun owners than you might expect. In The Post’s poll, 31 percent of Republicans and 37 percent of people who live in households that have guns support a buyback program. In the NPR survey, 20 percent of Trump voters backed O’Rourke’s proposal. That’s about the same figure as the percentage of Democrats who oppose the idea.

Granted, that was before it was associated with O’Rourke. In our political climate, assigning partisan support to something tends to affect how it’s viewed by the other party. But in the abstract, a mandatory buyback program is supported by about half the country.

But what we wanted to evaluate is the politics here. Dipping into the Post-ABC poll, we can overlay a potential 2020 contest — Trump vs. former vice president Joe Biden — with views of an assault weapons ban and a mandatory buyback program. While Biden leads Trump among all Americans by 54 to 38, he leads Trump 73-to 18 among those who support an O’Rourke-style buyback. The margin for the ban on new sales is about the same.

(Philip Bump/The Washington Post)

Note that there are slightly more people who back Biden but oppose a buyback than there are people who back Trump but support it. In other words, while 18 percent of those who support a buyback would choose Trump over Biden, 31 percent of those who oppose a buyback would choose Biden over Trump.

Perhaps some of that 31 percent are more moderate voters who would flip from Biden to Trump over the assault weapons ban. Maybe — but when we break the same numbers out for a theoretical contest between Trump and Sen. Elizabeth Warren (D-Mass.), things don’t change much. Thirty percent of those who oppose a buyback like Warren over Trump, basically the same level of support.

This gets at a fundamental question in the 2020 contest: Which is more important, ideology or party? How important is energizing the electorate? There are a lot of reasons to assume that O’Rourke’s proposal would be fiercely opposed by conservatives, most of whom weren’t going to vote for him anyway. Would it similarly invigorate liberals, spurring more turnout in the Democratic base?