FORWARD presence - deterring aggressors by massing forces in potential conflict areas - is a constant challenge for a budget-conscious military. Heavy armor and battlefield weapons and other elements of large-scale deployments can only move by sea, and sea transit is slow. A major power needs far-flung bases, or quick transport.
This simple fact underlies the recent call by Adm. William Owens, vice chairman of the Joint Chiefs of Staff, to ratify the new Law of the Sea Convention. Owens's challenge to the Senate to set aside this season's isolationist-internationalist debating and ratify the treaty was not an exercise in sentiment or naive multilateralism. The navigation rights guaranteed by the treaty will strengthen US defense capabilities.
The treaty sets out a right of ''transit navigation'' - permitting military vessels, such as carrier battle groups and protective fighter escorts, to take a straight line course even within 12 miles of shore.
One litmus test for the treaty is in a hypothetical deployment from the US naval base at Yokosuka, Japan, to the Persian Gulf- spigot for much of Europe's and Japan's oil. Transit navigation rights permit a battle group to snake its way through the island groupings of Southeast Asia - the shortest course to the Middle East.
Without transit rights, a battle group would have to proceed around the southern pacific coast of Australia, adding 15 days and fuel costs of $2.9 million for six ships.
Transit rights also permit strategically important US nuclear submarines to remain submerged while passing though straits. Many essential sea lanes pass close to powers not always aligned to US interests. Even friendly countries may be reluctant to associate themselves with US military actions. Under the treaty one can avoid questions of political delicacy in a crisis.