Apart from Abraham Lincoln, the greatest legacy of the Republican Party is the 14th Amendment to the Constitution.

Enacted by a GOP-controlled Congress after the Civil War, the 14th Amendment officially and decisively overruled the Supreme Court’s odious Dred Scott decision and redefined citizenship for all Americans.

For more than a century, it’s been interpreted by the Supreme Court to include children whose parents are not American citizens, including illegal immigrants.

“That is the wisdom of the authors of the 14th Amendment: They essentially wanted to take this very difficult issue — citizenship — outside of the political realm,” Washington Post columnist Michael Gerson, a former speechwriter for George W. Bush, said on ABC’s “This Week.” “They wanted to take an objective standard, birth, instead of a subjective standard, which is the majorities at the time. I think that’s a much better way to deal with an issue like this.”

Now some Republicans are looking to change that.

Led by U.S. Sen Lindsay Graham, R-S.C., they want to deny automatic citizenship to the sons and daughters of illegal immigrants. Idaho Sen. Jim Risch, along with Senate Republican leader Mitch McDonnell of Kentucky and Whip Jon Kyl of Arizona and House Minority Leader John Boehner of Ohio, have said it’s an idea worth considering.

They’re wrong. Messing with the 14th Amendment is not only dangerous, it’s an affront to everything the Republican Party stands for.

Refusing citizenship to some people born in the United States and not to others opens up Pandora’s box. If the offspring of illegal aliens can be denied citizenship, how about children of foreign nationals who are here legally? What about the children of naturalized citizens? Or the sons and daughters of those who hold unpopular opinions?

What if some future administration wanted to proscribe citizenship to the children of Muslims or any other religious group? Or of socialists or Tea Party members? Would that be OK?

The 14th Amendment is the single ironclad guarantee that politics can’t drive citizenship in this country.

And the notion of rewriting the amendment is opposed by, among others, Bush and former Vice President Dick Cheney.

Besides, it’s simply not going to happen.

“Good luck with that,” Bill Ong Hing, a professor at the University of San Francisco School of Law, told the website politco.com. “It can’t be a serious proposal on the part of those who are talking about it. Politically, it can’t be done and it’s a distraction from seeking true immigration reform.”

That’s the key point. We don’t need to change the Constitution. We need serious, comprehensive immigration reform on the federal level, and the political will to enforce it.

Some of the same people who want to rewrite the 14th Amendment are seeking to repeal the 17th Amendment, which provides for direct election of senators.

But it seems to us that the Constitution as it’s written is what makes America what it is. We’d no more support changing the 14th Amendment than we would altering the Second Amendment.