WASHINGTON – There's been a noticeable exception to President Donald Trump's otherwise successful effort to appoint young, conservative judges to the nation's appellate courts.

The Senate has confirmed a record 24 new circuit court judges nationwide in 20 months — with two more nominees scheduled for votes this week. But Trump has made far less progress in the jurisdiction he criticizes the most: the liberal-leaning U.S. 9th Circuit Court of Appeals, including California and eight other Western states.

Since Trump took office, the Senate has confirmed only one 9th Circuit judge — in Hawaii — leaving seven openings. A nominee in Oregon was abruptly withdrawn last month when it became clear he lacked the votes for Senate approval.

And Trump has yet to even nominate anyone for the three vacancies in California, partly because of a standoff with Sens. Dianne Feinstein and Kamala Harris.

But there are signs that the administration is beginning to set its sights on the 9th Circuit, likely triggering a bruising fight with Democrats.

For one thing, Trump is running out of vacancies in other circuits, particularly in conservative states where confirmation is easier.

"They've been focusing on lower-hanging fruit," said Ilya Shapiro, a senior fellow in constitutional studies at the Cato Institute. "After a while there are only so many seats to fill."

More than half of the 13 vacancies remaining nationwide are on the 9th Circuit.

Why Trump isn't moving faster is a mystery, considering how conservatives have long reviled the 9th Circuit and Trump has frequently attacked its rulings.

Since his inauguration, 9th Circuit judges have ruled that he couldn't legally bar tens of thousands of visitors and immigrants from several mostly Muslim nations from entering the country (a decision the Supreme Court overturned). They've forced him to continue processing renewal applications of immigrants previously approved for the Deferred Action for Childhood Arrivals program, which Trump ended. Last month, a judge knocked down Trump's order restricting federal funds to so-called sanctuary cities.

"I thought they would have moved more aggressively," San Francisco appellate attorney Ben Feuer said.

But the recent fight over Ryan W. Bounds' nomination in Oregon showed that Trump and the Republican-led Senate are ready to adopt a tougher stance, including scrapping a long-standing Senate tradition to push through Trump's choices if necessary.

Oregon's two Democratic senators, Ron Wyden and Jeff Merkley, opposed Bounds and refused to issue their "blue slips," a century-old courtesy in which senators are asked to sign off on nominees from their state.

In the past, rejection by both home state senators was enough to effectively kill a nomination. But for the first time, Judiciary Committee Chairman Charles E. Grassley of Iowa brushed off the home senators' views and moved forward anyway.

Previously the Senate has only considered a nomination if both or at least one of the home state senators approved.

Bounds' nomination ultimately failed, but not because the Oregon senators didn't return their blue slips. Instead some of Bounds' old racially charged writings raised doubts among enough senators, including at least one Republican, that the White House withdrew his nomination.

But the precedent of breaking with the blue-slip tradition has deep implications for the 9th Circuit, where four of the nine states it covers have two Democratic senators.

Idaho's Republican senators support Trump nominee Ryan D. Nelson, so he is quickly moving through the process without a problem.

And Hawaii's two Democratic senators enthusiastically backed Trump nominee Judge Mark J. Bennett as a consensus pick who had already been vetted by their review committees. He was approved in July by a 72-27 vote.

But the rest of the vacancies will not be so easy.

Trump nominated appellate attorney Eric D. Miller of Washington state though he was not recommended by the review committee created by the state's Democratic senators, Patty Murray and Maria Cantwell. Murray says she's reserving judgment on Miller, but Cantwell's office immediately signaled another potential fight ahead, telling the Seattle Times that "the senator did not and does not consent to Eric Miller's nomination."

In Arizona, where Trump doesn't get along with either Republican senator, he's held off as well.

Trump is saving the biggest battle for last. In California, talks between the administration and the state's senators appear to have stalled.

The White House floated some potential names, which the senators' review committees have examined. In early May, Harris and Feinstein recommended three potential judges to the White House. Neither side would say if there was any overlap between the two groups, but the lack of any nomination suggests there was not.

A White House official said the president intended to fill the 9th Circuit vacancies with more conservatives, but would not provide any timeline.

The recent focus on completing the confirmation of Judge Brett Kavanaugh to the Supreme Court could be delaying action in the 9th Circuit, though it hasn't stopped the Senate from voting on other judicial nominees.

Feinstein said in a statement that they are working to come to consensus.

Trump's best chance to reshape the 9th Circuit will be filling two of the vacant California seats once held by liberal lions: Judge Harry Pregerson, who took a reduced workload in 2015 and died in late 2017, and Judge Stephen Reinhardt, who died unexpectedly in March. Both were President Jimmy Carter appointees and were considered among the most left-leaning judges in the country.

Judge Alex Kozinski, who was appointed by President Ronald Reagan, retired in December amid accusations of sexual misconduct, creating a third California vacancy.

Though Trump is within striking distance of flipping some circuits from a majority of Democratic appointees to a majority of Republican appointees, the best he can hope for so far in the 9th would be increasing the conservative presence on the court.

Before Trump took office, the 9th Circuit had 20 Democratic and nine Republican appointees. If Trump filled all the current openings with conservatives, the balance would be 16 Democratic appointees to 13 Republican appointees.

Feinstein, the ranking Democrat on the Senate Judiciary Committee, is livid about Republicans' willingness to move forward without the blue slips and has warned them publicly against proposing nominees in California she and Harris don't support.