Oregon is joining nearly two dozen states suing the Trump administration over auto emissions regulations. 

Attorney General Ellen Rosenblum announced Friday that she’s joining a lawsuit in response to federal attempts to roll back standards adopted by California.

California has long had permission to set tailpipe standards that are more strict than federal law. More than a dozen states have opted to follow those standards, including Oregon and Washington.

Now, as the Trump administration seeks to weaken emission regulations nationwide, it’s moved to eliminate California’s unique authority. Attorneys general from 23 states and the District of Columbia are challenging the move.  

Rosenblum called the lawsuit a “no-brainer,” accusing the Trump administration of protecting big oil.  Washington Attorney General Bob Ferguson said this week that the president’s approach will help accelerate climate change. 

The lawsuit is the first step in what could be a lengthy fight. Many observers expect the issue to be decided by the Supreme Court.