IT DOESN'T TAKE a brilliant student of local government to figure out the virtues of regional cooperation -- but when local budgets around the country are being squeezed, political strains can easily rip apart fragile good-neighbor policies. It was money, after all, that led to a boom in regionalism; federal grants for pooled programs produced shotgun marriages of governments across all combinations of state and local boundaries. But just as good budgets made good neighbors, bad times are making many elected officials testier about how many they are willing to ante up for joint ventures.

Unfortunately, this region hasn't been spared the beginning anyway of a breakdown in cooperation. Just this week, for example, while officials were signing an important regional agreement on how the giant Blue Plains treatment plant will be shared, Montgomery and Prince George's counties were back at war over a proposal to build a composting plant, and Montgomery and District officials were in a sludge fight as well.

Earlier this year, officials in Northern Virginia nearly came to blows once again over which taxes to seek from Richmond for transportation and how those revenues would be collected and divided. Thanks to cool heads and help in the right places, that dispute was resolved. But what will the next one be about? Housing? Where there are water and sewer wars, you're talking housing, too.

The politicians are talking austerity, for good reason. But what they either do not recognize or fail to mention are the savings and efficiency that can be realized through jointly run programs. Pull-outs and go-in-alone movements are expensive propositions. Whether as members of the Metro board or of the Metropolitan Washington Council of Governments, the more responsible elected officials in this area should go to extra lengths to continue what has been an impressive record of regional cooperation over the years.