The latest crackdown on pornography began just as the nation’s high court was sinking yet another government effort to enforce notions of decency on American business.

New York’s man of letters, Attorney General Andrew Cuomo, sent one to Comcast Corp. threatening legal action for Comcast not signing onto his plan to eradicate child pornography from the Internet.

Cuomo has to threaten litigation, as did his predecessor Eliot Spitzer, so that he can demonize corporations in public. It’s effective because companies, who tend to want to avoid making a scene, often settle without admitting guilt.

That’s great for Cuomo, because quite frankly, the New York Attorney General’s Office has trouble winning actual courtroom proceedings. (See: Richard Grasso.)

But when it comes to stamping out lecherous material in the electronic world, no do-gooder wins in court. On Monday, a federal appeals court threw out a $550,000 fine against CBS Corp. for the split-second peep show by Janet Jackson at halftime of the 2004 Super Bowl.

Tuesday, the same appeals court once again upheld a ban on the 10-year-old Child Online Protection Act. (That was passed long before any of us were Googling “Paris Hilton” or “Client No. 9.”)

That act and one passed in 1996 were efforts by Congress to protect minors from objectionable content. It did so by imposing criminal sanctions, including penalties of up to $50,000 per day and up to six months in prison, for publishing material harmful to minors.

As laudable as the goal sounds, the courts repeatedly have found the means to it unconstitutional.

Comcast, AT&T and AOL are in a public relations no-win zone. Defy Cuomo and they’re viewed as defenders of corruption. Remove porn content and they’re derided as oppressors of free speech.

People go to jail for possessing and distributing child pornography. It is a crime. But laws that require Internet service providers to police the online red-light district, including inarguably offensive and criminal child pornography, rather than law enforcement aren’t going to hold up in court.