WASHINGTON Three years ago, Congress raised the age requirement for tobacco products from 18 to 21 in order to make America a little healthier.

Senate Minority Leader Mitch McConnell (R-Ky.) championed the change, which he said would help stem the tide of early nicotine addiction among youth in Kentucky and across the nation.

Though the tobacco industry embraced Tobacco 21 as an alternative to more aggressive measures, it was still a policy shift that showed Congress could take decisive action to protect public health.

But after two teenagers in New York and Texas legally purchased firearms in order to slaughter more than 30 people for fun and despite the fact that gun injuries are the leading cause of death among children its unlikely Congress will make it illegal to sell guns to teenagers anytime soon.

Licensed gun dealers can sell shotguns and rifles to 18-year-olds, but federal law restricts licensed handgun sales to buyers 21 and older. Unlicensed sellers people who arent professional gun dealers can sell handguns to anyone 18 or older. There are no federal age restrictions for unlicensed sales of long guns.

The gunman who murdered 19 children and two adults in Uvalde, Texas, last week legally purchased two semi-automatic rifles from a licensed dealer days after his 18th birthday.

Some states, such as Florida, have enacted new gun laws in response to mass murders. In 2018, after the Parkland school shooting in which a 19-year-old killed 17 people, Florida Republicans bucked gun rights groups and helped pass legislation banning gun sales to those under 21.

But a bill raising the minimum age for gun-buying seems unlikely to get through Congress due to opposition from Republicans and gun groups like the National Rifle Association.

I dont yet know exactly whats possible, whether the votes are there to raise the age, but were having a discussion about what we do about that specific profile. And its an encouraging conversation, Sen. Chris Murphy (D-Conn.) said Sunday on ABCs This Week.

Murphy is spearheading a renewed round of bipartisan negotiation in the Senate that is focusing on narrowly tailored gun control measures, including proposals to bolster school security, enhance background checks and incentivize states to pass red flag laws that allow authorities to temporarily seize firearms from people who have been determined to be a danger to themselves or others.

Its not clear yet which, if any, of these measures can gain at least 10 Republican votes to pass in the evenly divided Senate. Many Republicans told HuffPost last week they disliked the idea of raising the age requirement or doing anything at all.

I got my first rifle for Christmas when I was 14, Sen. Roger Marshall (R-Kansas) said. You know, I think this is just not the time to be trying to change major policies. I think this is the time to mourn with the people that have lost loved ones to reflect and to try to figure out whats really causing these. And I dont think weve done that yet.

Sen. Richard Burr (R-N.C.) said he would be open to new legislation that could actually stop a mass shooter, but he didnt think disallowing licensed rifle sales to 18-year-olds would have prevented the recent mass shootings by 18-year-olds.

Im not sure that the answer would be yes, just by changing the age, Burr said. If that were the case, we wouldnt have illegal purchases of tobacco or beer.

Researchers have found that when states raised their legal drinking ages to 21 in the late 1970s and early 80s, alcohol consumption declined among the targeted age group, and motor vehicle crashes also fell. Congress raised the minimum age for tobacco products in 2019 based on expert guidance that it would reduce smoking. The cigarette maker Altria warned investors that it expected cigarette sales volume to fall by as much as 6% in 2020.

Still, other Republicans also suggested that new federal gun laws would be powerless to stop determined 18-year-old mass murderers. Those who want to break the law will find a way to get around the law. Thats just the facts, Sen. Steve Daines (R-Mont.) said.

The fastest way to stop a bad guy with a gun is a good guy with a gun. Thats what happened in Texas, Daines said last week before it came to light that police officers in Uvalde waited almost an hour to confront the gunman .

Sen. Marco Rubio (R-Fla.) conceded that raising the minimum age required to buy an assault-style rifle could be something that prevents some [mass shootings] in some of these cases, but he argued other measures would be more effective, like boosting school security and passing red flag laws.

Rubio also noted that the law his state passed raising the age at which one can buy a weapon is being challenged in court by the NRA . In 2008, the Supreme Court ruled in a 5-4 decision that the Second Amendment to the U.S. Constitution protects an individuals right to own a gun.

The Second Amendment and federal courts recent interpretations of it are big reasons its so hard to pass federal gun laws. The sale of tobacco, by contrast, has no such protections in the Constitution or elsewhere.

The Senate is expected to hold a vote on gun reforms after it returns from recess next week. Democrats have vowed to move forward even if the group of bipartisan senators cannot reach an agreement.

Meanwhile, House Democrats are preparing a package of broader gun control measures, including a bill that would raise the minimum age to 21 for licensed sales of semi-automatic rifles that can accept magazines with more than five rounds of ammunition. The age restriction would not apply to unlicensed sales or to military service members. The House action will likely not amount to much, because the Senate will ignore it.

The push to increase the minimum age for tobacco purchases reflected a growing scientific understanding of the harmfulness of tobacco and the impressionableness of young peoples minds, said Matt Myers, president of the Campaign for Tobacco Free Kids.

The science has grown to demonstrate that 18- to 21-year-olds still make decisions that they wont make later in life that have potentially devastating, harmful effects, he said.

There isnt much willingness among Republicans to admit that easy access to guns might be harmful, much less that its worth legislating about, but attitudes can change.

If anybody had proposed raising the age of tobacco products to 21 20 years ago, they would have been shut down immediately, Myers said.