Washington — Democratic Senator Kyrsten Sinema of Arizona on Monday defended the filibuster as the Senate prepares to take a procedural vote on a sweeping voting rights bill, saying the rule "compels moderation" and helps shield the country from policy swings or reversals driven by changing party control.

"Instability, partisanship and tribalism continue to infect our politics," Sinema wrote in an published by the Washington Post. "The solution, however, is not to continue weakening our democracy's guardrails. If we eliminate the Senate's 60-vote threshold, we will lose much more than we gain."

Some Senate Democrats have been pushing to eliminate the legislative filibuster, which requires 60 votes to advance a bill in the Senate, to allow measures to pass with a simple majority. Because Democrats only hold 50 seats in the upper chamber, votes from 10 GOP senators are needed to overcome a filibuster.

Republicans, meanwhile, are expected to filibuster an expansive voting rights measure, called the For the People Act, set to be taken up by the Senate on Tuesday, blocking the legislation from advancing as it would fall short of the 60 votes needed for the bill to move forward.

The expected blockade from Republicans has fueled calls from progressive Democrats for the filibuster to be eliminated outright or reformed, paving the way for the Democratic-controlled Congress to enact President Biden's agenda. But moderate Democrats like Sinema and Senator Joe Manchin of West Virginia oppose doing away with the rule.

"To those who want to eliminate the legislative filibuster to pass the For the People Act (voting-rights legislation I support and have co-sponsored), I would ask: Would it be good for our country if we did, only to see that legislation rescinded a few years from now and replaced by a nationwide voter-ID law or restrictions on voting by mail in federal elections, over the objections of the minority?" Sinema wrote in the Washington Post.

Instead, the Arizona senator urged her colleagues to debate the filibuster, allowing their fellow senators and constituents to "hear and fully consider the concerns and consequences" of the matter.

"It's no secret that I oppose eliminating the Senate's 60-vote threshold. I held the same view during three terms in the U.S. House, and said the same after I was elected to the Senate in 2018," Sinema said. "If anyone expected me to reverse my position because my party now controls the Senate, they should know that my approach to legislating in Congress is the same whether in the minority or majority."

Sinema noted that when Republicans controlled the Senate, Democrats used the filibuster to block police reform and a COVID-19 relief bill, which forced GOP senators back to the negotiating table. Bipartisan policies, she said, "stand the test of time" and bolster Americans' confidence in government.

"My support for retaining the 60-vote threshold is not based on the importance of any particular policy. It is based on what is best for our democracy," she wrote. "The filibuster compels moderation and helps protect the country from wild swings between opposing policy poles."