SOUTH LAKE TAHOE, Calif. — Protecting this natural wonder, set in a mountain-ringed bowl 6,225 feet atop the Sierra Nevada, would have been difficult enough. But its placement, straddling the California-Nevada border, brings the two states into play, with sometimes-competing visions for the lake’s future.

For more than four decades, California and Nevada have worked to control development around Lake Tahoe. But that compact came close to falling apart after legislators on the Nevada side chafed at the way environmental concerns dominated the discussion, especially after the economic downturn battered Nevada’s casino economy.

Still, 12 years of negotiations resulted last December in a new development plan for the region that satisfied political leaders from both states and some environmental groups, providing a pathway for more construction in town centers around the lake, a few taller buildings and the possibility to expand some lakeside casinos, ski resorts and other facilities.

But it did not satisfy the Sierra Club, which believes the plan will open the door to much more development than proponents claim. Joined by a few smaller environmental groups, like the Friends of the West Shore, the Sierra Club filed suit to overturn the deal.