The United States has always been defined by the oceans. For centuries they've separated our nation from potential invaders. They also have served as a lifeline, providing abundant food in colonial times and vital trade today. About 20 percent of the world's oceanbourne trade passes through American ports.

So it makes sense that the Bush administration would want to protect America's freedom of access to the oceans. Unfortunately, it's trying to take a big step in the wrong direction.

For the second time in three years, President Bush has asked the Senate to ratify the United Nations Convention on the Law of the Sea (widely known as LOST, or Law of the Sea Treaty). The Senate Foreign Relations Committee has taken it up.

This is not the first time LOST has come up, of course. International negotiators drafted it in 1982 in an attempt to establish a comprehensive legal regime for international management of the seas and their resources. President Ronald Reagan, however, refused to sign LOST because he realized that the treaty doesn't serve U.S. interests.

In 1994, however, President Clinton signed a revised version of the treaty and forwarded it to the Senate. The record shows that the Senate was not convinced that the 1994 changes corrected the problems, and it has deferred action on the treaty ever since.

Despite the current administration support, the treaty remains a bad deal for the United States.

It does contain some provisions that would be marginally beneficial to the U.S. Navy, but that's outweighed by other provisions. Those provisions regard settlement of disputes, royalties on the exploitation of resources on the deep seabed and the empowering of an additional U.N.-affiliated international bureaucracy, which pose far greater risks to U.S. interests.

In fact, if it's ratified, this treaty is likely to have unintended negative consequences for U.S. interests.

First, the treaty would put the United States under the sway of international organizations established by the treaty. We already often face regional, economic or political blocs that coordinate their votes to support outcomes counter to U.S. interests in other international bodies. This also will likely happen with bodies set under LOST.

Second, bureaucracies established by multilateral treaties often lack the transparency and accountability necessary to ensure that they are untainted by corruption, mismanagement or inappropriate claims of authority. The LOST bureaucracy is called the International Seabed Authority Secretariat, which has a strong incentive to enhance its own authority at the expense of state sovereignty.

For example, this treaty would impose taxes on U.S. companies engaged in extracting resources from the ocean floor. This would give the treaty's Secretariat an independent revenue stream that would remove a key check on its authority. After all, once a bureaucracy has its own source of funding, it needs answer only to itself.

When international bureaucracies are unaccountable they seek to insulate themselves from scrutiny and become prone to corruption. The International Seabed Authority Secretariat is vulnerable to the same corrupt practices that have bedeviled the United Nations for decades.

The Bush administration is likely to argue that this treaty has real benefits. For example, it will probably claim the United States needs to join LOST to "lock in" the navigation rights it enjoys under customary international practice.

This assumes that other nations, the vast majority of which are already LOST participants, will ignore their obligations under the treaty unless we sign. In fact, we already enjoy most of the benefits of the treaty without having signed it.

The administration also will probably say U.S. companies won't take advantage of the economic opportunities afforded by extracting natural resources from the deep seabed unless the United States joins LOST. But American mining rights actually would be less clear under the treaty than they are today. This treaty won't help American companies. Indeed, because it promises to increase taxes, it'll hurt them.

Finally, the administration will claim the U.S always can prevent decisions that aren't in its interests. This, too, however, is unlikely. In nearly all cases, decisions of the treaty's secretariat may be adopted by a majority or two-thirds vote of members present and voting "if all efforts to reach a decision by consensus have been exhausted." Thus in many instances the United States will find itself outvoted and overruled.

The United States should be wary of joining sweeping multilateral treaties negotiated under the auspices of the United Nations. Specifically, the benefit to U.S. national interests should be indisputable and clearly outweigh the predictable negative consequences of ratification.

A fair Senate hearing will reveal that the United Nations Convention on the Law of the Sea doesn't meet this standard. It's time to cast it adrift.

Baker Spring is a Research Fellow in National Security Policy and Brett Schaefer a Fellow in International Regulatory Affairs at The Heritage Foundation (heritage.org).