A temporary 1 percent tax on motel room bills, approved four years ago to help advertise the Lewis and Clark bicentennial, may become permanent, a move supporters say would boost tourism.

"We don't do enough to promote tourism," said Sen. David Nething, R-Jamestown. "And I think that we've more than received the return we were promised when we do put money into tourism."

Senators voted 27-18 on Friday to approve a bill, which now moves to the state House, that would abolish the tax's June 30 expiration date. Should the tax continue, it is expected to raise more than $3 million from motel guests during the next two years.

Other lawmakers said making the tax permanent would break a promise made when the tax was first approved in 2003. It was advertised as a way of financing the state's advertising and preparation for the Lewis and Clark bicentennial celebration.

Sen. Ralph Kilzer, R-Bismarck, said North Dakotans would be skeptical about any future claims that a tax was temporary. It is 1 percent of a person's motel bill if the stay is less than 30 days.

"I think we should retain our credibility and not go back on our word that we gave to the citizens four years ago," Kilzer said.

On orders from President Thomas Jefferson, Meriwether Lewis and William Clark began a trip up the Missouri River in May 1804 to explore the Pacific Northwest. The expedition ended in September 1806, and the bicentennial celebration, which featured two "signature" events in North Dakota, is over.

"This (tax) was put on for one thing, and we said … we've got a sunset here," said Sen. Stan Lyson, R-Williston. "We never take a tax away, and now, we're going to prove that. … This was ridiculous (four) years ago, and it's ridiculous today."

Gov. John Hoeven's budget recommendations anticipated the loss of the tax. His suggested Department of Commerce budget included $3.76 million in added general fund money for tourism promotion. North Dakota's tourism agency is a division of the Commerce Department.

Sen. Tracy Potter, D-Bismarck, who supports keeping the tax, said the revenues it raises have been multiplied by the state's tourism promotion efforts. Motel operators who resisted the tax have benefited from it, Potter said.

"Tourism needs a dedicated source of funding related to the agency's own success at bringing people to North Dakota," Potter said. "The statewide lodging tax has been an unqualified success."

The bill is SB2258.