President Trump supports a GOP plan to break up the Ninth Circuit, which has been hostile to some of his policies, especially his travel bans, the Washington Examiner reports here.
Apparently Congress would create another circuit, that would include the state of Washington, which is generally more conservative than California (as well as Alaska, but Hawaii might be more liberal).
Trump still insists he was right on the travel bans and on opposing funding to sanctuary cities. A federal judge stayed that plan earlier this week on 10th Amendment arguments, claiming the federal government perhaps cannot micromanage how states manage their own law enforcement priorities.
Along these lines, Wikipedia has useful article on unitary vs. federal sovereign countries.