California lawmakers already are preparing for a legal brawl with the Donald Trump administration – and they’ve got President Obama’s former top attorney in their corner.

Top state Democratic lawmakers announced Wednesday that former Attorney General Eric Holder has been tapped as outside counsel to advise the Legislature on potential challenges with the Trump government. He will lead a team from the Covington & Burling law firm, where he’s been working since leaving the Obama administration in 2015.

“With the upcoming change in administrations, we expect that there will be extraordinary challenges for California in the uncertain times ahead,” California Senate President pro Tempore Kevin de León and Assembly Speaker Anthony Rendon said in a statement. “This is a critical moment in the history of our nation. We have an obligation to defend the people who elected us and the policies and diversity that make California an example of what truly makes our nation great.”

They said Holder and his team will advise “in our efforts to resist any attempts to roll back the progress California has made.”

The statement did not specify which policies they anticipate will cause friction, though California’s numerous sanctuary cities are likely to face challenges from an administration that has threatened to pull their federal funding.

In an interview with the Los Angeles Times, De León suggested Holder’s team will work on issues like immigration, climate change, the environment and voting rights.

The unorthodox arrangement assigns to Holder’s team some duties that normally would be handled by the state’s top law enforcement official, the California attorney general. Gov. Jerry Brown has nominated Democratic Rep. Xavier Becerra for that job.

The Los Angeles Times reported that De León and Rendon have been considering hiring outside counsel ever since Trump’s election, in a preemptive bid to protect state policies that could clash with the new administration’s.

Holder was one of Obama’s longest-serving and most controversial Cabinet members.

He had a contentious relationship with congressional Republicans, who in 2012 voted to hold him in contempt of Congress for not turning over documents on the Fast and Furious “gun-walking” scandal.

He left in 2015 to rejoin Covington & Burling.

Holder said in a statement Wednesday he is “honored” to work with California’s Legislature “as it considers how to respond to potential changes in federal law that could impact California’s residents and policy priorities.”