Nearly all elected politician – from the president down to local city counselors – want to criminalize flag burning. No decent American wants to see our flag being desecrated. It’s a popular issue and politician glom on to popular issues. 

That is why we have a Supreme Court: to prevent elected politicians from compromising unpopular basic liberties, such as freedom of expression for those whose views and actions we despise.

The late Justice William J. Brennan once said that if he saw someone burning his beloved American flag, he would punch him in the mouth, but he wouldn’t try to convict him of a crime.  I would do neither. But nor would I applaud or join in the disgraceful display of anti-American hate. 

PRESIDENT-ELECT TRUMP'S THREE GREATEST CHALLENGES

The situation with regard to flag burning is exactly where it should be in a Democracy: nearly everyone despises flag burners, but the constitution forbids us from making it a crime. 

The Constitution would also forbid President-elect Trump to take away the citizenship of flag burners. 

The Supreme Court has not only held that flag burning is constitutionally protected, but also that citizenship cannot be taken away even if a flag burner could be convicted of a crime.  Denial of citizenship based on a criminal conviction has been ruled to be unconstitutional.

So President-Elect Trump is wrong on at least two counts:  you can’t criminalize flag burning; and you can’t take away the citizenship of flag burners.

As president, Trump may have the power to change the constitutional status of flag burning, by appointing justices who agree with the minority in the most recent 5-4 flag burning decision. 

The late Justice Scalia was in the majority in that case, and if his replacement takes the minority view, the Supreme Court may change its decision.  That would be a serious mistake, because of respect for precedent and because it would open a slippery slope for denying other basic freedoms of expression. 

Candidate Trump would seem content with that, since he advocated changing the libel laws to make it easier to sue his critics.  But any such change may boomerang against Trump himself, who uses defamation as a political weapon. 

If the constitutional rules were loosened, Trump might be subject to defamation actions for calling people crooked, corrupt and other defamatory epithets. Being president doesn’t immunize the incumbent from being sued for mouthing off against his opponents.

So let’s leave the First Amendment alone. Let flag burners be ridiculed and despised in the court of public opinion. Let’s not make martyrs of them by hauling them before our courts of law. 

The First Amendment has served us well for two and a quarter centuries.  It has protected extremists both on the right and left.  Most Americans, when polled, would prefer to ban speech they dislike: “Free speech for me, but not for thee.”  

If Donald Trump had his druthers, he would interpret the First Amendment to protect what he says and does, while at the same time, permitting the government to punish what his critics – and those with whom he disagrees – say and do. But that is not the way freedom operates.  Freedom of speech for anyone is freedom of speech for everyone.  And denying freedom, of speech to anyone, has the potential of denying it to everyone. 

The First Amendment is not broken so let’s not try to fix it.  Freedom of expression is a principle that liberals and conservatives alike can and should support.  Historically it has always been opposed by extremists on both the right and the left, who have no patience for dissenting points of view. 

So President-elect Trump, please withdraw your tweet, develop a thicker skin for criticism, and stop tinkering with our freedom of expression. 

If you ever see someone burning the American flag, don’t call the cops and don’t punch him in the nose.  Just remind him that the flag he is burning is what protects his right to burn that flag.

Alan Dershowitz is emeritus professor at Harvard and author of "Taking the Stand: My Life in the Law" and most recently, "Electile Dysfunction: A Guide for the Unaroused Voter".