TRAVERSE CITY, Mich. | A year ago, it seemed a proposed compact designed to prevent raids on the Great Lakes might be sunk by squabbles in the states with jurisdiction over nearly one-fifth of the world's fresh surface water.

Now the deal is close to ratification on the state level, and supporters are beginning to plot strategy for the final step: winning approval from Congress and the White House.

On the surface, the task would appear easy. Congress has endorsed more than 200 interstate compacts over the years, including 41 dealing specifically with water management. They regulate use of some of the nation's primary water sources, such as the Colorado and Delaware rivers.

Leading supporters of the Great Lakes pact say they're aware of no significant opposition in Congress or from the Bush administration. Sens. John McCain and Barack Obama, the likely presidential nominees, have endorsed it.

But backers remain wary. After all, it was fear of water grabs from other sections of the country -- or even from overseas -- that inspired the eight states to negotiate their deal.

"There's a sense of urgency because this is an increasingly valuable natural resource at a time when significant growth is taking place in water-short areas," said David Naftzger, executive director of the Council of Great Lakes Governors.

The governors were jolted into action a decade ago when a Canadian firm obtained a permit from Ontario to ship tankers of Lake Superior water to Asia. The company dropped its plan in the face of withering criticism. But legal experts said the lakes needed stronger protection.

After years of haggling, the governors signed the compact in December 2005. They couldn't make a binding agreement with Ontario and Quebec, but both provinces adopted laws nearly identical to the compact.

It would prohibit, with rare exceptions, piping or shipping Great Lakes water outside the system's vast drainage basin, which reaches from the mouth of the St. Lawrence River to beyond the western edge of Lake Superior near Duluth, Minn. The basin measures about 900 miles east to west and 700 miles north to south.

Also, the states would be required to adopt conservation plans and regulate their use of water -- not just from the Great Lakes, but also inland waterways.

"It was declared dead several times before the governors came out with their recommendation," said Andy Buchsbaum, director of the National Wildlife Federation's Great Lakes Natural Resource Center. "It's been declared dead every couple of months since then. But it keeps coming back, like a cat with nine lives."

Associated Press writer Marc Levy in Harrisburg, Pa., contributed to this report.