Senators should be wary of changing rules to weaken the filibuster, the chamber's Republican leader is warning.

Senate Minority Leader Mitch McConnell (R-Ky.) dug in against proposed changes to the filibuster — one of the principal tools he's used in the past two years against Democrats' majority — in an op-ed to be published in Wednesday's Washington Post.

"For two years, Democrats in Congress have hoped their large majorities would make it easy for them to pass extremely partisan legislation," McConnell wrote. "Now that they've lost an election, they've decided to change the rules rather than change their behavior. They should resist the impulse."

The GOP leader did not rule out compromise on rules changes in the Senate outright. He suggested, for instance, that changes to allow Republican senators in the minority to offer amendments could be a good first step.

"Why would Republicans vote for action on a bill that, we've been promised, we'll be blocked from contributing to in any way?" he asked. "If the majority wants more cooperation, it could start by allowing differing views to be heard."

But McConnell seemed cool to rules changes proposed by some Democrats that would undercut Republican procedural tactics that have slowed or halted some bills.

"Even worse, any rule change aimed at making it easier for one party to force legislation through the Senate with only a slim partisan majority would undermine the Senate's unique role as a moderating influence and put a permanent end to bipartisanship," McConnell said, referencing a vote against a similar rules change by Senate Republicans in 1995, when they were in the majority.

Democrats are working through options to change the rules for when the new Senate formally convenes. Leading Democratic senators spearheading reform efforts believe they can change the rules with a simple majority vote on the first day of the new session. The date on which that vote can occur is expected to come later in January.