With less than two years under his belt, President Trump has managed to make a substantial imprint on the U.S. judicial system — one that could be felt for decades to come — by getting the Senate to confirm key judicial nominees.

The fundamental shift has come even as Republicans grumble that Democrats are slow-walking the process in the Senate. Democrats have been demanding maximum debate time for many of Trump's picks, but even with that obstacle, the courts aren't lacking for Trump nominees.

“What President Trump has done with judicial selection and appointments is probably at the very center of his legacy, and may well be his greatest accomplishments thus far,” Leonard Leo, an outside adviser to the White House on judicial selection and executive vice president of the Federalist Society, told the Washington Examiner.

“By the end of this year, he probably will have transformed about 30 percent of the federal appellate courts in our country, and that’s quite significant when put against other administrations in modern history," he said.

Liberals mostly hate Trump's choices.

“Most of the nominees confirmed for the court of appeals seats manifest an exceptional level of hostility to workers, women, consumer rights, environmental protections and people of color,” Nan Aron, president of the Alliance for Justice, told the Washington Examiner. “They’re selected specifically because of the hostility revealed in their records.”

But more are coming. There are currently 80 Trump judicial nominees in the Senate pipeline between the appeals courts, district courts, and the U.S. Court of Federal Claims, according to the Administrative Office of the U.S. Courts.

Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, has said he's pushing to have the Senate vote on every appeals court nominee — seven are currently pending in the Senate and there are 14 current vacancies — by November.

Already, the upper chamber has confirmed 21 of the president's picks to the appeals courts, nominees to which Republican Senate leaders have placed a priority.

Republicans are hoping to continue with this pace, and they realize the Senate is having an impact. After six more judges were confirmed by the Senate in the last 10 days, Senate Majority Leader Mitch McConnell, R-Ky., said the effort is starting to bear fruit.

“One-eighth — one-eighth — of the circuit judges in America have been appointed by Donald Trump and confirmed by this Republican Senate,” McConnell told reporters Tuesday. “We think we’re making dramatic progress on that front.”

And Republicans are hoping to go even faster.

Under Grassley's leadership of the Judiciary Committee, he's interpreted the "blue slip" in a manner different from his immediate predecessor, Sen. Pat Leahy, D-Vt. The blue slip allows a home-state senator to weigh in on a judicial nominee.

Leahy strictly enforced the practice, and didn't move nominees unless home-state senators approved.

But Grassley has maintained that the blue slip is a courtesy and has said that as long as the White House has consulted with home-state senators, an unreturned blue slip would not preclude an appeals court nominee from receiving a confirmation hearing.

The move has outraged Democrats, but Grassley points out that the Senate has made this decision before.

The change in practice will be tested when Trump starts focusing on the nominees for the liberal 9th Circuit, when California's two Democratic senators, Sens. Dianne Feinstein and Kamala Harris, are likely to argue strenuously that they need to signal their approval before the Senate considers judges from that state.

There are currently seven vacancies on the San Francisco-based court, three of which are California seats.

Many Democrats can see the change coming as more of Trump's picks are confirmed.

“By packing the court with so many extreme nominees, President Trump and, in my view, sad to say, the Senate Republicans, want to undo years of progress and change American law and life for the worse,” Sen. Mazie Hirono, D-Hawaii, said Thursday at a Senate Judiciary Committee hearing.

Republicans are considering moves to speed up the process even more, by forcing lawmakers to stay on nights and weekends to eat up debate time more quickly.

“I have pleaded with McConnell to work nights, to work Saturdays and weekends, and put the pressure on the Democrats,” Grassley told radio host Hugh Hewitt last week. “And we’ve got to have every Republican around and even cancel a recess so we can clear the calendar of these important nominees. Otherwise, all the hard work I’m doing in committee is for naught.”

That hasn't happened yet, but Trump himself has called on the Senate to stay in Washington more often to get the job done, and it's possible McConnell will feel pressure to move in that direction.

Given that reality, Democrats have been mostly left to hope that they can somehow win back the Senate and once more take control of the agenda, which might be their only real option.

“What happens with the midterm elections will have real impact on this,” Leo said. “If the Senate changes hands, all bets are off, and frankly, I think it’s highly unlikely we will see any court of appeals confirmations at least."