The lessons of the Treaty of Tordesillas -- which marks its 486th anniversary this Saturday -- have not been lost on the modern-day American bureaucracy. Especially in agencies seeking to protect, expand or define their turf.

That treaty, in case you've forgotten, was aimed at keeping Spain and Portugal from hacking one another to ribbons during the period when they were hot to explore and colonize the new world, which turned out to be us.

The June 7, 1494, agreement, mediated by the pope, divided the world in half. Spain got exclusive rights to explore everything 370 leagues west of the Cape Verde Islands. Portugal got the other side. This is why they speak Portuguese in Brazil and Spanish in most other places in South America.

Aware that Portugal got the territorial shaft, lawyers for federal agencies now realize that lines on maps are important. The Interior Department is always tripping over the Agriculture Department's jurisdiction, and vice versa, just as the State Department and the Pentagon sometimes get their wires tangled. At any rate, it is considered vital in government to decide who can do what, and where. And get it in writing.

With that in mind, understand that the Federal Labor Relations Authority was naturally concerned, when it was created, that it could have jurisdictional squabbles between its regional offices as they mediate internal labor-management squabbles in our globe-girdling government.

FLRA regional offices are responsible for investigating, processing and prosecuting unfair labor practice charges in agencies. The Washington Office (Region 3), for example, has been most careful to mark off its turf in the most specific geographic terms. Its charter, for example, defines its jurisdictional lines like this: ". . . Region 3's jurisdiction includes the District of Columbia, Maryland, Virginia, West Virginia and all land and water areas east of the continents of North and South America to longitude 90 degrees east, except the Virgin Islands, Panama (limited Flra jurisdiction), Puerto Rico and the costal islands."

Anybody who tries to step over that line to referee an in-house government fight stands to be zapped by the FLRA.