Analysis By James Arnold BBC News Online business reporter

A television, a Reagan-era US regulator once said, is just "a toaster with pictures" - a device so basic, with such a homogeneous product, that the idea of special treatment is laughable.

Two decades later, under another Republican president, the regulators' kid gloves are at last coming off.

The Federal Communications Commission (FCC) has just voted to relax the United States' 28-year-old rules on media ownership - rules that, among other things, prevent a company controlling both a TV station and a newspaper in the same town.

A sensible update, its proponents argue; a threat to democracy, say its opponents.

In fact, the rule change may be most significant in what it says about the vacuity of US media regulation.

Out of time

US media ownership rules were certainly in need of sprucing up.

Created in the idealistic post-war years, and finalised under the presidency of Jimmy Carter, they place draconian restrictions on the type, size and number of media outlets any firm can own.

The idea, according to a landmark Supreme Court judgement in 1944, is that "the widest possible dissemination of information from diverse and antagonistic sources is essential to the welfare of the public, that a free press is a condition of a free society."

But, the reformers argue, such considerations carry less weight in a world where media choice has been vastly widened by technology and increasing household incomes.

In 1975, the three main US TV networks had 95% of the prime-time audience; now, the top four have less than 50%.

And rules preventing cross-media ownership also deny consumers potential benefits, media firms say - not least the notion that local news can be delivered better by a more muscular print-broadcasting-online outfit.

Crying foul

But such intangible media efficiencies cut little ice with opponents.

The US is a far more provincial media business than most European countries: with many Americans getting their news almost exclusively from local sources, there is a genuine fear that ambitious firms could achieve near-monopolies in certain areas.

Jack Balkin, a professor at Yale law school, argues that it would take "an act of superhuman self-restraint" for media moguls to avoid influencing the news in their captive markets.

Even Ted Turner, the man who founded CNN, has said that he could never have launched the channel in such a potentially oligopolistic business.

Nor is this just the argument of bleeding-heart liberals.

The National Rifle Association, which represents US gun-owners, fears that control will pass into the hands of "gun-hating" metropolitan media conglomerates.

'Crapshoot'

They may be wrong; they may be right.

The real problem with the rule change is that no-one really has any scientific data proving either case.

The FCC, stung by the level of public outcry, has reacted chippily, refusing to consult much with the public, or to allow more time for debate.

This makes its liberalisation a "roll of the dice", Martin Kaplan, a respected media academic, argued in a recent Christian Science Monitor article.

"It would be hard to imagine Thomas Jefferson entrusting the future of democracy to a crapshoot."

Regulator, heal thyself

Indeed, the decision throws an uncomfortable spotlight on the role of the FCC, one of the US's more peculiar agencies.

Monday's vote was achieved because three of its five commissioners are now from the Republican party, and therefore automatically in favour of deregulation.

The two Democrat commissioners, meanwhile, were equally stubborn in their refusal to dismantle rules.

Yet these five politicos preside over a regulatory jurisdiction of extraordinary size: not just media, but all communications by radio, wire, satellite and cable - a parcel of interests put together long before the gigantic size of the online industry became apparent.

The FCC hopes that, by updating its media-ownership rules, together with ongoing updates to its position on such arcana as wireless networks, it can secure a role as a regulator for decades to come.