WASHINGTON – It's been 150 years since the Supreme Court added seats to its bench and 82 years since a president tried. The court's conservative evolution over the past three years, however, has persuaded a cottage industry of left-wing groups to try, try again.

The brewing debate over the shape and structure of the high court, as well as lower federal courts, could influence the Democratic race for the party's 2020 presidential nomination and further politicize the nation's judiciary following three brutal confirmation battles.

Both sides are eager for a brawl.

Democrats contend that Republicans have taken over the Supreme Court illegitimately, first by blocking President Barack Obama's effort to install a fifth liberal justice in 2016 and then by confirming President Donald Trump's two nominees in 2017 and 2018, the latter by a narrow 50-48 margin.

Republicans are more than happy to elevate the courts to marquee status in the 2020 elections, noting Trump benefited from the 2016 fight that followed Associate Justice Antonin Scalia's death and the failed Supreme Court nomination of federal appeals court Judge Merrick Garland.

The clash over courts has taken a back seat to other issues, from the economy and health care to immigration and climate change. But liberal activists argue that a failure to counter Trump's drive to create a conservative judiciary could doom the entire liberal agenda.

"You cannot have a democracy when one side is stealing courts," says Aaron Belkin, a political science professor at San Francisco State University whose brainchild, Take Back the Court, advocates adding four justices to the high court's nine-seat bench.

His solution also calls for expanding the size of federal circuit and district courts to compensate for seats Republicans blocked Obama from filling. To achieve any of it, Democrats first would need to win the White House and majorities in Congress – "a very steep lift," Belkin admits.

Brian Fallon has a more realistic goal. As director of Demand Justice, the former press secretary for both Hillary Clinton's 2016 presidential campaign and Attorney General Eric Holder wants to make the courts a high-profile political and policy issue. That includes pushing term limits for judges and naming potential Supreme Court nominees in a Democratic administration – something Fallon plans to do soon.

"We need to demystify the court, make it something that seems within reach of political activism," Fallon says. "The primary campaign is a good window of time to try to do this."

To which Republican activists say: Bring it on. The growth of liberal groups pushing judicial issues prompted Mike Davis, nominations counsel for the Senate Judiciary Committee during the most recent high court confirmation fight, to create his own group.

Davis' Article III Project, named for the Constitution's establishment of the judicial branch, has a simple goal: to fight for Trump's federal court nominees and "defend new judges against left-wing attacks."

"A big part of what we want to do is just amplify their message," Davis says of liberal court-packing advocates. "All they're going to do is fire up conservatives."

That worries nonpartisan court reform advocates such as Gabe Roth, executive director of Fix the Court, which favors term limits along with Supreme Court ethics and transparency initiatives.

“Court reform has become more of a political football than I want it to be," Roth says. "Proposals for court-packing invite this race to the bottom.”

Garland, Gorsuch, Kavanaugh

The liberals' effort to pack the court is more than a long shot.

Though the Constitution does not limit the number of Supreme Court justices, which has varied from five to 10 over the years, the Judiciary Act of 1869 set the number at nine, and it hasn't changed since.

The closest call came in 1937, when President Franklin D. Roosevelt proposed giving himself the power to name up to six more justices who would back New Deal legislation. That effort died in the Senate along with its chief sponsor, who suffered a heart attack.

Democrats were similarly outfoxed in 2016, when Scalia's sudden death while on a hunting trip in Texas presented Obama with a dream opportunity and Republicans with a nightmare scenario: replacing the court's conservative leader with a fifth liberal justice. Senate Republican leader Mitch McConnell refused even to hold a hearing on Garland's nomination, and the vacancy lasted until Trump's election.

Since then, the Senate has confirmed Associate Justices Neil Gorsuch and Brett Kavanaugh, solidifying conservative control of the court. Trump has named 129 lower court judges, including 43 to powerful circuit courts, which is 41 more than Obama got through the Senate in his final two years.

Liberal advocacy groups pushing initiatives such as Medicare for All and a Green New Deal now see their chances blocked not only by a Republican White House and Senate but conservative judges and justices. The Supreme Court, they note, has allowed unlimited corporate spending on elections, struck down the heart of the Voting Rights Act and shut federal courthouse doors to claims of partisan gerrymandering.

"Something needs to change, because the status quo is bad for democracy," Fallon says. "We want to push the envelope. We want to be disruptive."

His volunteers are working in the nation's capital and early caucus and primary states such as Iowa and New Hampshire, seeking to pressure Democratic presidential candidates and local activists to raise the issue of court reform.

So far, success has been limited. In Washington, a few more Senate Democrats have voted against Trump's lower court nominees. On the campaign trail, nine White House hopefuls have declared themselves "open" to ideas such as court-packing.

Leading the pack on that issue is Pete Buttigieg, the South Bend, Indiana, mayor who has proposed a 15-member Supreme Court. Five members would be affiliated with Democrats, five with Republicans, and five would be chosen by the other 10. Former Rep. Beto O'Rourke of Texas last month proposed 18-year term limits for justices.

Other candidates have been less enthusiastic, including former Vice President Joe Biden and Sen. Bernie Sanders of Vermont. In New Hampshire, the suggestion of court-packing prompted moderate Sen. Michael Bennet of Colorado to slam his head on a table four times.

Not even the leader of the Supreme Court's liberal wing buys the idea. Associate Justice Ruth Bader Ginsburg told National Public Radio last week that adding seats was a bad idea when Roosevelt was president and remains so today.

"If anything would make the court look partisan, it would be that – one side saying, 'When we're in power, we're going to enlarge the number of judges, so we would have more people who would vote the way we want them to,'" Ginsburg said.

Nominee lists, term limits

Liberal groups led by the Alliance for Justice already are assembling a list of potential high court nominees for a Democratic president who would vote the way they want them to. That has prompted conservatives to call for them to name names, which Trump did in 2016.

"The American people ought to have a clear idea of what a president would do in terms of nominations," says Carrie Severino, chief counsel at the conservative Judicial Crisis Network and a former law clerk for Associate Justice Clarence Thomas. "This is one of the longest-reaching and most impactful decisions that a president will make."

Many credit Trump's lists of Federalist Society and Heritage Foundation favorites with helping him win election. Polls revealed that 26% of Trump's voters called it the most important factor, compared with 18% of Clinton's voters.

"Please make the next election about judges," Davis says. "Please."

A less political solution for what ails the Supreme Court – aging justices, toxic confirmation battles, the taint of partisanship – may be to replace the Constitution's promise of life tenure with term limits. Roth's group would set the term at 18 years, so that a new justice would be named every two years.

A growing list of legal scholars supports ending life tenure, but implementing it would be difficult. Either it would require a constitutional amendment or Congress would pass legislation requiring that justices retire, take "senior" status with lesser duties, or move to an appeals court.

"There are implementation challenges with any proposal," Roth says.

Associate Justice Stephen Breyer has endorsed the idea. He said in April that "long terms" such as 18 years would "make life easier. I wouldn't have to worry about when I'm going to have to retire or not."

While the majority of Supreme Court justices have not signed on to any proposal, they at least agree they can't serve forever. The court in February overturned a ruling by the full U.S. Court of Appeals for the Ninth Circuit because its author had died before it was filed.

"That practice effectively allowed a deceased judge to exercise the judicial power of the United States after his death," the high court said in an unsigned opinion. "But federal judges are appointed for life, not for eternity."