(Wine-Searcher) - A proposed rule change by the U.S. Bureau of Indian Affairs could lead to new casinos in California's wine country.

How would Napa Valley look with a casino and a 12-story hotel in the middle of the now-scenic horizon? That's the nightmare the county fears if the U.S. Bureau of Indian Affairs goes through with a proposed rules change.

The new rule, if passed, would make it easier for Native American tribes to gain federal recognition. One tribe currently suing the U.S. government for recognition claims its ancestral lands include "the great valleys of Sonoma and Napa Counties, including Alexander, Knights, and Napa Valleys."

If a tribe is recognized it is exempt from many local and state laws – notably development laws – on its "trust land." A federally recognized tribe in Napa Valley would not have to follow the county's agricultural protection law.

"This is all about a casino. Napa's the bullseye," says Rex Stults, government relations director for Napa Valley Vintners. "A (recognized) Indian tribe is a sovereign country. It's like inviting a foreign nation into the county. Fifty years of observing the agricultural preserve would go right out the window."

The tribe in question, the Mishewal Wappo Tribe of Alexander Valley, is down to 340 living members, according to its website. Its leaders could not be reached for comment on this story.

The Wappo lost federal recognition in the 1950s. In 2009, the tribe sued the U.S. government to regain that status. Napa and Sonoma Counties joined the U.S. government in opposing the suit, but in 2012, the presiding judge removed the counties from the case.

The most recent hearing in the case was in July of 2013. Stults attended and said: "The judge really zeroed in on the holes in the Wappo argument. I was sitting there with the people from Sonoma County and we thought: it would be great if he made a decision here and now."