While much of the nation is focused on the health of ailing Supreme Court Justice Ruth Bader Ginsburg, President Trump’s more immediate and unending concern is the notoriously liberal U.S. Court of Appeals for the 9th Circuit.

“Everything goes to the 9th Circuit,” Mr. Trump complained Friday in a bit of hyperbole. “Everything.”

Senate Republicans’ padding of their majority in the midterm elections will allow Mr. Trump to move forward with his goal of reshaping the 9th Circuit, as part of his record-setting push to put more conservative judges on circuit courts. The Senate Judiciary Committee will take up five more of Mr. Trump’s judicial nominees Tuesday, including one appeals court judge.

The 9th Circuit’s actions on a single day last week illustrated why Mr. Trump wants to change the ideological makeup of the sprawling appeals court, which covers nine Western states and two territories.

A three-judge panel of the 9th Circuit ruled on Thursday that Mr. Trump cannot stop an Obama administration program that protects young immigrants living in the U.S. illegally from deportation.

On the same day, a federal district judge in Montana — part of the 9th Circuit — blocked construction of the Keystone XL oil pipeline, saying the Trump administration ignored the project’s impact on climate change. The judge, Brian Morris, is an Obama appointee.

Mr. Trump signed an executive order on his second day in office approving the Keystone pipeline, which had been blocked by President Obama. The energy project became a symbol of Mr. Trump’s “America First” economic resurgence.

“It was a political decision made by a judge,” Mr. Trump lamented Friday. “I think it’s a disgrace. It’s 48,000 jobs. I approved it; it’s ready to start.”

He knows where the case is headed in the appeals pipeline.

“I guess they’ll end up going to the 9th Circuit, as usual,” Mr. Trump said pessimistically.

The appeals court, based in San Francisco, is authorized for 29 judges, and it has six vacancies. Of the 23 current judges, 16 were appointed by Democrats and seven by Republicans.

That means if Mr. Trump fills all the vacancies, the 9th Circuit’s balance would be 16 Democratic appointees and 13 Republican — not a flip in ideology, but closer to partisan parity. The president has three nominations pending.

“We’re slowly putting new judges in the 9th Circuit,” the president said.

Democratic senators are not happy about it, either. Sen. Patty Murray of Washington state objected late last month to Mr. Trump’s nomination of Seattle lawyer Eric Miller, a member of the conservative Federalist Society, to the 9th Circuit.

“I am not going to be complicit in this latest rushed process to load the courts with Trump nominees in the lame-duck session,” she said, calling the president’s nominees “extreme conservatives.”

Mrs. Murray refused to return her “blue slip” on the nominee — a senatorial tradition essentially giving veto power to a senator over judicial candidates from their home state. But enforcement of the courtesy has varied over the years, and Senate Republican leaders say the won’t allow the objection of a home-state senator to block a nomination.

Sen. Lindsey Graham, South Carolina Republican who is eyeing the chairmanship of the Judiciary Committee next year, said he won’t allow Democrats to take advantage of the blue-slip tradition.

“We’ll get their input, but they’re not going to have a veto on the circuit court,” Mr. Graham told radio host Hugh Hewitt last week.

In 2013, Democrats erased the 60-vote threshold to end a filibuster for most nominations. That means Republicans can continue to push forward with Mr. Trump’s judicial nominees, after already having set a record with 29 circuit court confirmations so far in his presidency.

Senate Majority Leader Mitch McConnell, Kentucky Republican, said the midterm election results of Democrats winning the House majority should provide even more momentum for the GOP’s drive to install Mr. Trump’s judges.

“I think we’ll have probably more time for nominations in the next Congress than we’ve had in this one, because the areas of legislative agreement will be more limited between a Democratic House and a Republican Senate,” Mr. McConnell said last week. “I don’t think we’ll have any trouble finding time to do nominations.”

The president said the 9th Circuit’s ruling on the Obama-era immigration program, called Deferred Action for Childhood Arrivals or DACA, was actually a positive for his administration despite losing the case. The action means the case is no longer in the hands of the 9th Circuit.

“You rarely win in the 9th Circuit,” Mr. Trump said. “The good news is, by rejecting DACA in the 9th Circuit we’ve been waiting for that. We get to the Supreme Court, and we want to be in the Supreme Court on DACA.”

While Mr. Trump is actively trying to change the makeup of the 9th Circuit, he’s essentially already done that with the Supreme Court in less than two years. His two high court nominations, Justices Neil M. Gorsuch and Brett M. Kavanaugh, have given the court a 5-4 conservative majority.

While Justice Ginsburg’s hospitalization last week for broken ribs sparked intense speculation about a possible open seat on the high court, her retirement wouldn’t be as pivotal as the departure of Justice Anthony M. Kennedy, who was a swing vote.

Mr. Trump has a well-known list of potential Supreme Court nominees, including Judges Thomas Hardiman of the U.S. Court of Appeals for the 3rd Circuit, Raymond Kethledge of the 6th Circuit, William H. Pryor Jr. of the 11th Circuit, Amy Coney Barrett of the 7th Circuit and Amul Thapar of the 6th Circuit.

Justice Ginsburg, 85, was discharged from the hospital Friday, and is expected to resume her work on the court quickly. Asked about her injury, the president said, “I wish her well.”

“I hope she serves on the Supreme Court for many, many years,” Mr. Trump said.