BIAS AND BIGOTRY have a thousand disguises and are exercised under an infinite variety of ploys and pretexts. In Culpeper County, Va., where a proposal to build a mosque for the county’s tiny Muslim community met an outpouring of local intolerance, the bigotry masqueraded as a dispute over sewage.

Culpeper, about 70 miles southwest of Washington, D.C., is a largely rural county, population 50,000. When Muslims of the Islamic Center of Culpeper — a grand-sounding name for a community numbering fewer than 20 — wanted to build a structure on a small parcel of land for their prayer services last spring, the request seemed routine. Because the soil at the site could not handle a septic system, the center was told to apply for a pump-and-haul permit, which would allow sewage to be stored in an on-site tank and trucked away periodically.

No big deal: Since 1992, Culpeper has considered 26 such pump-and-haul permit requests for commercial and religious use — roughly one a year, on average — and each one has been granted, including nine for churches. But when the Islamic Center’s request came before the seven-member county board, suddenly things got complicated.

According to a lawsuit by the Justice Department , which alleges that the board discriminated against the center in denying the permit, the trouble started in February when a local Republican activist wrote the following to some supervisors: “I understand the Islamic Center of Culpeper wishes to rehabilitate the existing home and use it on a weekly basis as a place of prayer. . . . Hmmmmmmmmm.” That triggered a wavelet of local opposition, which culminated in the board’s decision to deny the permit in April, on a 4-to-3 vote before a chamber of cheering citizens.

The bigotry behind the board’s vote was transparent. The activist acknowledged he was bothered about Islam having a foothold in the county. Both the county administrator and the county attorney admitted that similar requests, including one a few months earlier, had been approved without a second thought. The zoning for the land in question authorizes the construction of houses of worship “by right.” And the local health department had verified, as it does routinely in such cases, that the center was justified in seeking a pump-and-haul permit as a matter of “hardship,” since the land would not support a septic system.

In the absence of a mosque, the handful of Muslim worshippers are left to worship at a small house on the site of a used-car dealership. The closest existing mosque, which is not in the county, is 45 minutes away by car.

Culpeper has a choice. It can reverse itself in the interest of honoring one of this nation’s proudest founding precepts, as enshrined in the First Amendment: freedom of worship. Or it can be known nationally as an exemplar of prejudice and sectarian intolerance in a time of rising chauvinism.