(CNN) Beto O'Rourke is back in the middle of the 2020 conversation, following his proposal during last week's third presidential debate that AR-15s and AK-47s would be subject to a mandatory gun buyback program if he is elected president.

The question is whether O'Rourke's proposal -- and the newfound prominence it's given him in the race -- will doom congressional Democrats' attempts to make a deal with President Donald Trump on a background check bill in the wake of a serious of recent mass shootings.

"I don't know of any other Democrat who agrees with Beto O'Rourke, but it's no excuse not to go forward," Minority Leader Chuck Schumer of New York told local reporters earlier this week as he tried to get himself -- and his Senate Democratic counterparts -- as far away from the mandatory buyback proposal as possible.

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Far from backing away in the face of Schumer's criticism, O'Rourke went right back at the Senate's most powerful Democrat. "Ask Chuck Schumer what he's been able to get done," O'Rourke told reporters in Colorado Thursday night . "We still don't have background checks. Didn't have them when he was in the majority either."

That stance is winning O'Rourke plaudits among liberals who had been waiting (and waiting) for the former Texas congressman to show some of the flashes that made him a national phenomenon in his 2018 Senate bid. Suddenly, O'Rourke, who looked dead in the water heading into last Thursday's debate in Houston, now has a spark. And he's not going to let that go for anything -- especially scoldings from Senate Democrats like Schumer.

But, the politics of what's good for O'Rourke's presidential hopes don't align terribly well with congressional Democrats' goal of using the latest series of mass shootings to get something done on expanding background checks. Or passing any sort of further gun control measures.

For decades, Republican lawmakers -- fueled by the National Rifle Association -- have effectively cast the gun control debate in the starkest of possible terms: Give an inch to Democrats on their desire for what they call common sense gun safety measures and you are priming the pump for a day when the government will come and confiscate your weapons. See, the theory goes, all Democratic politicians want to come take your guns but they won't come out and say it. But, give them power and just watch what happens.

It's these inaccurate scare tactics that led to surges in gun purchases immediately following Barack Obama's victories in 2008 and 2012. During the 2016 campaign, Republicans seized on Hillary Clinton's expressed interest in an Australian buyback program as evidence of her secret intentions. "Of course Hillary does not support national mandatory gun buyback programs, including those modeled after Australia's program," a Clinton spokesman told PolitiFact

And yet, the canard persists. It's one of the main reasons that Congress has refused to act on things like universal background checks and other gun control measures that have broad spectrum support across the political world. Because, according to the NRA, even passing something that 90% of Americans say they want is the first step toward Democrats seizing your guns.

Now, the NRA has O'Rourke's "Hell, yes, we're going to take your AR-15, your AK-47" line during the debate to hang its ominous warnings on. And Senate Republicans -- and the Trump White House -- have it as a ready-made excuse for not acting on proposals that large swaths of the public support.

"Dummy Beto made it much harder to make a deal," Trump tweeted earlier this week. "Convinced many that Dems just want to take your guns away. Will continue forward!"

Texas Sen. John Cornyn, a Republican, told reporters earlier this week that O'Rourke's comments "has thrown gasoline on this discussion ... which had been proceeding along a pretty calm, logical and rational path. Added Cornyn: "Unfortunately, I think he set back the debate a lot -- maybe by not just years but decades."

It's still possible that a deal on guns is reached by Congress. But, even before O'Rourke's push on mandatory buybacks, Trump was dithering as he tried to navigate between his desire for a deal and his concerns about alienating the NRA and its legion of ardent voters. And history suggests that Senate Republicans would only move on guns if they felt that public pressure wouldn't allow them to do anything else.

While O'Rourke's call for mandatory buybacks of certain guns has enlivened his presidential candidacy, it's also provided a very clear -- and easy -- escape hatch for a White House and a group of Senate Republicans in search of one. Ah, politics.