WASHINGTON — The United States and Canada could easily have operated a joint Customs and Immigration station on U.S. soil had negotiations over shared border management not faltered last year, a federal report suggested.

In a letter to key lawmakers addressing shared border management, the U.S. Government Accountability Office reported that issues related to putting Canadian border agents on duty in the U.S. — possibly at Wellesley Island — were largely resolved and that few changes in U.S. law would have been necessary.

But negotiations faltered over how to run such a station in Canada, near Buffalo.

Officials considered Wellesley Island a top contender for such a station, although the GAO did not mention specific locations. With shared management no longer in discussion, the Department of Homeland Security is designing a scaled-back model for a new U.S. station at Wellesley.

The GAO reported that the two countries had agreed on all of the authority Canadian officers would need to operate in the United States, although officials had not decided where the U.S.-based station would be built.

Negotiators resolved many issues related to U.S. operations in Canada as well, including the arming of U.S. agents. But they remained locked in discussions about taking fingerprints from people who change their minds about entering the United States after initial review by border agents — an authority the United States claims but Canada does not.

The two countries also disagreed about arrest authority on Canadian soil, the GAO reported.

Negotiations continued for about two years until the Department of Homeland Security announced in April 2007 that it had failed to reach an agreement. The collapse made the envisioned shared border station on Wellesley Island a casualty as well.

The GAO wrote to Sen. Hillary Rodham Clinton, D-N.Y., as well as top appropriators for homeland security programs, following a requirement in this year's spending bill for DHS that officials report on the effort.

Mrs. Clinton and Sen. Charles E. Schumer, D-N.Y., have advocated for shared border management. After talks collapsed, Mr. Schumer urged that the new border station at Wellesley Island be designed nonetheless for the possibility of shared operations at some future point.

In a statement Thursday, Mr. Schumer said the report underscores that a shared station at the Thousand Islands is an efficient and safe way to move people and goods.

"Perhaps, under a new administration in Washington, we can take a fresh look at a good idea waiting for a leader to make it happen," Mr. Schumer said.