Retired Supreme Court Justice John Paul Stevens called for a repeal of the Second Amendment in a New York Times op-ed Tuesday, and he urged demonstrators pressing for gun control to do the same. His bold proposal has prompted many questions about whether such a fundamental change to the U.S. Constitution is legally – let alone politically – possible.

"For over 200 years after the adoption of the Second Amendment, it was uniformly understood as not placing any limit on either federal or state authority to enact gun control legislation," Stevens wrote.

That changed in 2008, when the Supreme Court ruled in the case of District of Columbia v. Heller that there is an individual right to bear arms. Stevens was one of four dissenters.

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"That decision – which I remain convinced was wrong and certainly was debatable – has provided the N.R.A. with a propaganda weapon of immense power. Overturning that decision via a constitutional amendment to get rid of the Second Amendment would be simple and would do more to weaken the N.R.A.'s ability to stymie legislative debate and block constructive gun control legislation than any other available option," Stevens wrote.

But just how "simple" – or difficult – is it to repeal a constitutional amendment, and how does the repeal process work?

Experts say there are two ways to go about it. The first process requires that any proposed amendment to the Constitution be passed by both the House and the Senate with two-thirds majorities. It would then need to be ratified by three-fourths of the 50 states – or 38 of them.

Historically, that's proved challenging.

The "arduous process has winnowed out all but a handful of the amendments proposed over the past 230 years," Ron Elving, senior editor and correspondent on the Washington Desk for NPR News, wrote earlier this month.

"Even relatively popular ideas with a big head of steam can hit the wall of the amendment process. How much more challenging would it be to tackle individual gun ownership in a country where so many citizens own guns — and care passionately about their right to do so?" Elving wrote. He pointed out the "tremendous support" gun ownership has in large parts of the nation, especially the South, West and Midwest, "which would easily total up to more than enough states to block a gun control amendment."

The second option for repealing an amendment is to hold a Constitutional Convention. In that case, two-thirds of state legislatures would need to call for such a convention, and states would write amendments that would then need to be ratified by three-fourths of the states.

While it's theoretically possible to change the Constitution this way, "that's never happened since the Constitution was ratified," said Kevin McMahon, an expert in constitutional law and a professor of political science at Trinity College in Hartford, Connecticut.

In the history of the United States, the only amendment that's ever been repealed is Prohibition. The 21st Amendment, in 1933, repealed the 18th Amendment, of 1919, which prohibited the making, transportation and sale of alcohol.

McMahon told CBS News it's "very unlikely" that the Second Amendment could ever be repealed.

"It's hard enough for gun control legislation to be passed now in the Congress which requires simply a simple majority," he said.

A repeal would require "a sea change" in how Americans think about gun control and the right to bear arms, McMahon said.

"I would never say it's impossible," but "it is very difficult to enact a constitutional amendment," he said.

Stevens' call for a repeal is not the first remark from a former member of the Supreme Court against the Second Amendment. As The Atlantic reports, former Chief Justice Warren Burger said in 1991: "If I were writing the Bill of Rights now, there wouldn't be any such thing as the Second Amendment."

Speaking on the MacNeil/Lehrer NewsHour, he said the amendment on "the right of the people to keep and bear arms" was the subject of "one of the greatest pieces of fraud – I repeat the word 'fraud' – on the American public by special-interest groups that I have ever seen in my lifetime."

Since then, there have been other calls to look again at the Second Amendment. Bret Stephens, a conservative columnist for the New York Times, has endorsed the idea of repeal, writing: "Gun ownership should never be outlawed, just as it isn't outlawed in Britain or Australia. But it doesn't need a blanket Constitutional protection, either."

Recently, filmmaker Michael Moore suggested rewording the amendment to say: "A well regulated State National Guard, being helpful to the safety and security of a State in times of need, along with the strictly regulated right of the people to keep and bear a limited number of non-automatic Arms for sport and hunting, with respect to the primary right of all people to be free from gun violence, this shall not be infringed."

Following last month's fatal shooting at a Florida high school, and as a movement rose out of the shooting, the national gun debate surged – once again – into the spotlight. Inspired by student survivors of the Feb. 14 Parkland massacre, an estimated 200,000 protesters gathered in Washington, D.C., on Saturday to push for gun control.

Stevens wrote in his op-ed that the demonstrations "demand our respect." But he said protesters "should seek more effective and more lasting reform."

"They should demand a repeal of the Second Amendment," he wrote.

Aaron Blake, senior political reporter writing for The Fix at The Washington Post, told CBS News that in his view, Stevens' op-ed was "about the most unhelpful thing" for the gun control movement.

"This is playing into the Republican talking point that this is the ultimate goal of gun control advocates, which is to take away guns, to not have gun ownership be a right, to repeal the Second Amendment," Blake said.

President Trump weighed in early Wednesday morning, tweeting: "THE SECOND AMENDMENT WILL NEVER BE REPEALED! As much as Democrats would like to see this happen, and despite the words yesterday of former Supreme Court Justice Stevens, NO WAY."