A progressive group is making a wonky case for Democratic Senate candidates: changing the hidebound chamber’s rules.

Oregon Democratic Sen. Jeff Merkley wrote in a new fundraising email, provided first to Roll Call, that electing Democrats to the Senate could lead to an overhaul of the Senate filibuster, or the 60-vote threshold needed to end debate on legislation and Supreme Court nominees.

“Democrats need to take back the majority,” Merkley wrote in an email for the Progressive Change Campaign Committee. “And if we do, it’s time to continue what we started on filibuster reform.”

In 2013, Democrats invoked the so-called nuclear option and changed the Senate rules to eliminate the filibuster for most nominees, except Supreme Court picks. But Republicans’ recent refusal to take up President Barack Obama’s Supreme Court nominee, Merrick Garland, has raised questions about whether Democrats would go further and lower the threshold for high court hopefuls.

[ Merrick Garland Trudges On, Awaiting Supreme Court Action ]

Merkley hinted that could be a possibility. He pointed to recent comments by GOP Sens. John McCain of Arizona, Ted Cruz of Texas and Richard M. Burr of North Carolina that indicated some Republicans would be willing to block any high court nominee that Democrat Hillary Clinton chooses, if she wins the White House.

“Republican Sens. Ted Cruz, John McCain, and Richard Burr are likely the tip of the iceberg,” Merkley wrote. “This idea doesn’t just blurt out randomly three times in a couple weeks.”

“I’m committed to continuing the push to reform filibuster rules so Senate dysfunction and abuse of the rules doesn’t keep obstructing the ability of the judicial and executive branches to do their jobs — and so the Senate can work for ‘we the people’ again,” Merkley added.

New York Sen. Charles E. Schumer, who is poised to become the next Democratic leader, has not said whether he would definitely change the Senate rules.

“I’m not going to speculate about if we get to a bad place,” Schumer recently told CNBC. “I’m going to work hard to get to a good place.”

So far, blocking all Clinton high court nominees does not appear to be a unanimous position.

Georgia GOP Sen. David Perdue, a member of the Senate Judiciary Committee, told reporters Monday that blocking all nominees would be “a dereliction of duty.”

“We are called to advise and consent. Now, we can say, ‘No,’ but that means you do have a hearing,” Perdue said.

“It shouldn’t be be done during the emotional period of a presidential election. Period,” Perdue said, explaining the GOP position not to consider Obama’s nominee.

“You have a new president — and I said it then — you have a new president and that president nominates, and we advise and we consent or we withhold consent,” Perdue said. “But you do have a hearing.” 

Contact Bowman at bridgetbowman@rollcall.com and follow her on Twitter @bridgetbhc.