As Democrats gear up for a fight over the future of the Supreme Court, some progressives are calling for a more aggressive approach from Senate Minority Leader and Park Slope resident Chuck Schumer, who they say is failing to lead the party in its uphill battle to block Donald Trump from filling the vacancy created by Justice Anthony Kennedy's retirement.

On Monday, hours before President Trump is expected to announce his nominee to the highest court, protesters with the grass roots group Indivisible will rally outside Schumer's Midtown office to urge the Democratic leader to "whip the vote"—or, to exert pressure on the Democratic caucus to form a united front against Trump's pick for the court.

Despite mounting pressure from the left, Schumer has thus far not signaled an interest in the type of arm-twisting that activists are calling for. Instead, his plan of attack rests on the prospect of unity between the two parties on the issues of the Affordable Care Act and women's reproductive rights. In an op-ed for the Times last week, the senator wrote that "the best way to defend those rights is for a bipartisan majority in the Senate to lock arms and reject a Supreme Court nominee who would overturn them."

Schumer's strategy has put him at odds with many left-leaning Democrats—a rift made worse by Schumer's failure to attend a long-scheduled town hall in Brooklyn last week (he claimed his plane was broken, and took questions by phone). "We are in a gunfight, and we have a butter knife," one town hall attendee told Schumer, WNYC reported.

In response, Schumer reportedly asked constituents to stop "prodding Democrats to use their limited procedural power to delay a Supreme Court confirmation." He also pushed back on some suggestions, like Sen. Cory Booker’s proposal to not vote on a nominee while the president remains under investigation, as too "partisan."

But according to members of Indivisible, it's Schumer's refusal to whip the vote that has left the door open for some red-state Democrats to vote for Trump's pick, as Senators Joe Manchin (W.Va.), Heidi Heitkamp (N.D) and Joe Donnelly (Ind.) did for Neil Gorsuch. They acknowledge that upcoming Senate races for those fence-sitting democrats may be putting the minority leader in an awkward position, but argue that the fight for the court seat is too consequential for Schumer to maintain his typical hands-off style of leadership.

"When it comes to preventing an appointment of an extreme Supreme Court Justice, the responsibility to lead lies squarely with Schumer," members of Empire State Indivisible wrote. "While it may be a challenge to peel off two Republicans to vote against these toxic nominees, Schumer's ability to lead shouldn't be."

In an email, NYU Law School Professor Deborah Archer, who has participated in several cases in front of the U.S. Supreme Court, told Gothamist that "the reality is that Democrats have limited options—they do not occupy the position that Republicans did when President Obama nominated Judge [Merrick] Garland."

"But, Schumer can make sure that all Democrats vote no, including those that represent red states, and he also needs to flip a moderate Republican," Archer said.

"One effective approach from the past was the mobilization against repealing the Affordable Care Act—mobilizing nationwide protests that put pressure on senators,” she added. “That may be an effective option here."

Following the rally outside Chuck Schumer's office this evening, protesters are expected to gather at Union Square at 8 p.m. to demonstrate against the president's pick. A "Rally to Save Roe" is also scheduled for Tuesday afternoon. You can learn more about how New Yorkers are mobilizing against the monumental Supreme Court appointment here.