For the first time in a decade, Democrats control the White House while enjoying narrow majorities in the Senate and House of Representatives, presenting the party with a key leadership test that could decide whether its majority will persevere after 2022.

This test lies with the elimination of the filibuster—a rule that imposes a 60 vote rule for most bills to move past debate, including legislation Democrats campaigned on: gun law reform, expanded voting rights, LGBTQ civil rights protections, and more.

With only 50 Democrats in the Senate, it's nearly impossible for even the most popular influential bills to gain 10 Republican supporters, thereby making them dead on arrival.

Most Democrats say the filibuster encourages the minority rule the founding fathers warned against, and was largely deployed to protect racist Jim Crow laws.

But while many Senate Democrats have voiced support for eliminating the filibuster, at least two Democrats—Senators Joe Manchin of West Virginia and Kyrsten Sinema of Arizona—say it's a nonstarter.

Manchin, however, has expressed some willingness to implement reforms allowing for some minority party input without kneecapping the majority party's agenda, such as lowering the 60 vote threshold required to pass debate.

But Senate Minority Leader Mitch McConnell (R-KY) delivered an insidious rebuke of that possibility in a Tuesday Senate floor speech.

Watch below.

Mitch McConnell offers 'SCORCHED EARTH' filibuster warningwww.youtube.com

McConnell warned that eliminating the 60 vote rule would result in a scorched earth Senate beyond any of their imaginations once the Republican party took power again.

The Senate Minority Leader said:

"Everything that Democratic Senates did to Presidents Bush and Trump, everything the Republican Senate did to President Obama, would be child's play compared to the disaster that Democrats would create for their own priorities if — if — they break the Senate."

That threat isn't empty coming from McConnell, whose tenure as Senate Majority Leader was marked by a refusal to pass almost all legislation sent by the Democratic House of Representatives, and the unwillingness to even consider the final Supreme Court nominee of former President Barack Obama.

Senator McConnell even eliminated the filibuster for Supreme Court Justices in order to get former President Donald Trump's nominations on the nation's highest court.

Twitter wasn't scared of McConnell's threats, noting his long history of scorched earth tactics.

Many are urging Democrats not to buckle under McConnell's threats, and to pass H.R. 1, the landmark voting rights legislation that would curtail Republican efforts to limit access to the ballot box.

Without at least some level of filibuster reform if not outright elimination, it's hard to imagine how Democrats will implement the ambitious platform that delivered them legislative and executive power over the country.