A federal court is considering the case of a California church whose historical status is being questioned after it was given taxpayer dollars to pay for its preservation.

The San Gabriel Mission (search), just outside Los Angeles, is one of 21 Spanish colonial landmarks that dot the California coast. After nearly 200 years of rain, wind and earthquakes, the elements have taken their toll.

"Now we have a moisture problem with water seeping up through the bottom of the floors," said Helen Nelson, who works for the mission. "To repair and restore it now, it'll take a little bit of money."

Last year, Congress allocated $10 million from taxpayer funds to help restore the historic structures. Now, the group Americans United for Separation of Church and State is suing to stop that money from being spent.

"Nineteen of these missions are active, worshipping congregations and I don't think it's the responsibility of the taxpayers of the country to bail out those or any other churches," said Barry Lynn, head of Americans United.

Mission preservationists and Catholic officials say nothing is unconstitutional about the appropriation and that, like the Old North Church in Boston, these are no ordinary houses of worship.

"They're historic monuments, they need to be preserved. They represent the earliest stages of California's history, of the nation's history," said Knox Mellon of the California Missions Foundation.

Both camps say they believe legal precedent is on their side.

"In a series of cases back in the 1970s, the Supreme Court was quite clear that if money is going for a so-called 'dual-use' building that is religious and secular, you can't get it from the taxpayers," Lynn said.

"I think you can document that, beginning in the mid-'90s, that there was a relaxation on the part of the federal government toward the use of federal monies for landmark structures that have had some sort of identification with religion," Mellon countered.

California Democratic Sen. Barbara Boxer (search) originally led the fight to get tax money for the missions, marking one of the few times she and President Bush have seen eye to eye on religion and government. No court date has been set for the case, but the $10 million to be used for the repairs will be held up until it is settled.

Click in the video box near the top of the story to watch a report by FOX News' William La Jeunesse.