FOR THOSE WHO may have heard the name but don't know what it applies to, Techworld is an ambitious high-technology trade mart, hotel and retail complex scheduled to be built opposite the D.C. Convention Center. And for those who may not realize it, Techworld has become a belated and inappropriate target of a federal government lawsuit that threatens the home rule authority of the District of Columbia government.

After negotiating all sorts of modifications and winning approvals from every pertinent local authority, Techworld and the city government are being challenged by the Justice Department on behalf of the Interior Department and the Smithsonian -- in an attempt to reclaim a one-block section of 8th Street NW that has been under the city's jurisdiction for a good century or more. The 8th Street right-of-way was closed by permanent legislation of the D.C. Council in November 1984, with agreements from Techworld's owners to preserve the vista. The project's building height was approved by the D.C. zoning administrator and the D.C. corporation counsel; and the National Capital Planning Commission -- which in effect represents the federal government's interest in such matters -- supported the street closing. In addition, if Congress had wanted to overturn the city government's actions, it could have -- but it didn't.

Yet last October, when construction was starting, two local organizations -- the Committee of 100 on the Federal City and the D.C. Preservation League -- raised the argument that Congress never gave the city authority to close 8th Street. No doubt that's because the District government has been closing streets and alleys for the past 100 years -- with not a single denial by Congress.

Whatever anyone may think of Techworld's beauty and merit, it has been reviewed every which way, and after modifications has won the support not only of the appropriate local agencies but also of business, civic and neighborhood organizations. That is how home rule -- local self-government -- is supposed to work. To toss the process aside at this point would be to replace local authority with worse-than-ever federal subjugation. The court should settle the matter and end costly delays by acting quickly to reject the suit.