IT WAS a private get-together of public officials -- with no formal agenda and no license to act as a body -- but the gathering assembled on Capitol Hill this week by Rep. Connie Morella (R-Md.) turned into an exceptional indicator of what the 1991 leaders of Greater Washington might accomplish in the next Congress. Joining those who will represent the region in Congress were the local leaders from throughout the area, all of whom cited the meeting as the start of unprecedented cooperation in seeking federal aid. Rep. Morella, referring to "a new breeze blowing through" the region's political circles, says efforts will include a push for more federal transportation money as well as discussions of the region's housing, education, crime and environmental issues.

Much of this new tone is the result of changes in the cast of players. With Sharon Pratt Dixon taking over from Marion Barry in the District and with Jim Moran replacing Stan Parris in Northern Virginia, area officials hope that the all-too-long era of trans-Potomac sparring will give way to joint legislative ventures. Rep. Steny Hoyer, long a leader of cooperative efforts on behalf of the region in Congress, is expected to call a meeting of area officials next month to discuss ways to improve relations between the District and Congress. Already, Mayor-elect Dixon's visits and calls to Capitol Hill and the suburbs have received good reviews -- reestablishing the mayor of Washington as the lead voice of the city in intergovernmental relations.

The changing cast also includes the leaders of two regional organizations that lead their fields nationally when it comes to expertise and results: the Metro system and the Metropolitan Washington Council of Governments. Carmen Turner, who headed Metro until this month, and Walter A. Scheiber, who is retiring next month as executive director of the Council of Governments, are highly regarded administrators who combined expertise, top-flight staffs and personal negotiating skills to generate unity for regional efforts of all kinds. The COG leadership will continue in good hands under Ruth Crone, who has been second to Mr. Scheiber and whose 21 years with the organization have included experience in human services, public safety, housing and planning.

The optimism is bound to be tempered to a degree by the economic pressures that will affect decisions from Capitol Hill to the farthest corners of the region. But if this metropolitan area is to get the fairest possible share of financial support under these circumstances, a strong regional approach is essential.