CABLE TELEVISION is providing, among other things, an interesting new form of political patronage. The cultural benefits of the cable systems have yet to be demonstrated to most of metropolitan Washington, but the political benefits are manifest. The current play in Prince George's County suggests the possibilities.

The county had got off to a good start, setting up an independent commission of citizens to guide it through the crucial process of awarding the franchises. After much careful consideration, in September, the commission made its recommendations for the two franchises, one for the northern half of the county and the other for the southern. Confronted with this disinterested advice, the county council voted, 6 to 4, to succumb to temptation. It rejected the advisory commission's choice and gave the northern franchise to another company--this one headed by Winfield Kelly, the former county executive. Mr. Kelly and his supporters on the council agree that it is totally irrelevant that they are all Democrats.

For the southern franchise, the council chose the company originally recommended for the other one --a company decorated with a carefully bipartisan selection of familiar political names. The whole emphasis on local ownership and community control in these cable competitions is turning into a travesty. The cable industry is being rapidly consolidated into a few very big systems that have become highly adept at organizing letterheads including the friends and associates of the people who will make the decisions on the franchises.

Cable television is not, in fact, a good field for small, locally financed enterprises. It's potentially very profitable, but, with inflation and high interest rates, the initial investments are proving unexpectedly high, and the payoffs are delayed. Arlington's cable company used the threat of financial distress to bludgeon the county government into rewriting its franchise last summer. Alexandria's genuinely local cable company, chosen with much care by the city council two years ago, has now announced that it hasn't the resources to continue and will sell out --at a substantial profit to the shareholders--to a national system.

Those governments still in the process of writing franchises--in this area, the District of Columbia and Montgomery and Fairfax counties--need to take note. The proper standards of selection are quality of service, financial strength--and nothing more. Local ownership is a fake. It provides nothing local but patronage of a highly expensive sort, with the bill ultimately to be paid by the local subscriber.