But the larger war over how California’s limited water resources are used seems far from over. The compromise’s approval is sure to spur new court battles. It could also embolden House Republicans like McCarthy and Devin Nunes, R-Tulare, and conservative think tanks to seek further changes in federal policies.

Environmental groups are expected to sue over new rules which allow federal authorities in charge of water supplies in the Sacramento-San Joaquin Delta to deliver more water to farmers in periods of drought.

The Endangered Species Act has been a potent weapon for environmental groups, which have often succeeded in getting judges to adopt broad interpretations of provisions that have been used to protect the delta smelt and Chinook salmon in Northern California waterways. This thinking is reflected in a lawsuit filed in March by green groups, which say even the strong environmental stances of federal and state regulators under Democratic President Barack Obama and Democratic Gov. Jerry Brown don’t go far enough in providing fresh water to the delta.

Such tactics awaited George W. Bush after he became president in 2001. His administration was stymied in efforts to shift environmental policies by legal action and effective lobbying in Congress. By one tally, environmentalists won 27 of their 38 suits against the two-term president.

Endangered Species Act long a Republican target

But the same attitude seen in Natural Resource Defense Council lawsuits against Democratic administrations — why settle for a good result when more is possible? — could soon animate Republicans, especially those who have chafed at how much control the federal government has over land-use decisions in the West. Nunes in particular has long railed against federal indifference to the concerns and needs of Californians.

The Washington consensus is that Feinstein cut a deal because of the fear that a Trump administration would go much further in revamping interpretations of existing water and endangered species laws. This led her to make a major concession to McCarthy: Allowing the secretary of commerce and the secretary of interior to play a key role in determining in how water is allocated between the Delta and farmers.

That provision alone could turn California water policies upside down.

Trump’s nominee for commerce secretary, billionaire investor Wilbur Ross, doesn’t have high-profile views on land-use issues. His nominee for interior secretary, Montana Rep. Ryan Zinke, is open to the federal government allowing much more of its land to be used for oil and gas drilling, but has spoken of the importance of preserving public lands.

There is also the possibility that the Trump administration could target the Endangered Species Act itself — either through executive orders reinterpreting the law or by encouraging congressional action.

Conservative think tanks have long faulted the species act for far more than denying water to Central Valley farmers. It’s viewed as the California Environmental Quality Act is seen by business groups and conservatives in the Golden State: as a blunt, coercive tool to win land-use battles.

A 2007 report by the Dallas-based National Center for Policy Analysis offers a framework for the sort of policies the Trump administration could pursue.

The most decisive — and most controversial — would simply be for the secretaries of commerce and the interior to make it more difficult to a species to be designated as endangered and easier for a species to be taken off the protected list, reducing the authority now wielded by the U.S. Fish and Wildlife Service. Conservatives have long argued that designations of 1,300-plus native species and plants are excessive and arbitrary.

President Obama has decided to side with Sen. Barbara Boxer and California environmentalists in their battle with Sen. Dianne Feinstein and House Republicans over Golden State water policy.

On Monday, Feinstein announced that she had reached agreement with legislative leaders to place a provision providing $588 million for California water storage, desalination and recycling projects into the massive omnibus infrastructure bill that’s expected to pass Congress by year’s end. The deal also included a change in water allocation rules that would take some supplies away from the Sacramento-San Joaquin River Delta and give it to Central Valley farmers temporarily for five years.

The announcement prompted relief among Central Valley politicians, who had been fighting for just such changes for years only to be turned back by Senate Democrats.

Reflecting this history, Boxer — in her final month as a California senator — was the sharpest critic of Feinstein’s compromise. She said the deal threatened the health of the delta and could harm the salmon fishing industry and kill off the endangered Delta smelt.

But hopes that the logjam might have been broken blew up Tuesday when the Obama administration revealed it shared Boxer’s objections to the California provision.

“Based on what we know so far, we don’t support the kinds of proposals that have been put forward to address some of the water resources issues in California right now,” White House press secretary Josh Earnest said, according to McClatchy News. “So, we don’t support that measure that’s being put forward, but we’ll take a look at the bill in its totality.”

Prospects for water changes strong under Trump

This could doom the proposal in the short term. But given how popular the omnibus infrastructure has been in recent weeks among lawmakers eager for a big legislative triumph, it may pass over an Obama veto.

Whatever happens in the next six weeks, on Jan. 20, when Donald Trump takes over as president, the Central Valley is likely to have the most sympathetic president it’s had in the 50 years since the environmental movement began racking up victory after victory in Congress and the courts.

Trump made appearances in the Central Valley in May and August, the first time for a rally in Fresno and the second for a fundraiser in Tulare. At the rally, he expressed contempt for policies that he said favored fish over human needs. He also appears to have a good relationship with Rep. Devin Nunes, R-Tulare, who has been among the loudest critics of state and federal water policies’ effects on the Central Valley.

Nunes was reportedly under consideration for secretary of agriculture in the days after Trump’s surprise Nov. 8 election, but his name hasn’t been heard as much in recent days.

The favorite for the job may now be former Georgia Gov. Sonny Perdue, who recently met with Trump about the position. Perdue, like Nunes, is often skeptical of heavy environmental regulation and comes from a state that has often balked at global warming activism.