With the party's midterm wins in November, Senate Democrats officially clinched control of their chamber for the next Congress. But it's now in the hands of Georgia voters to determine just how powerful their majority will be and how much difference Democrats can make in furthering President Joe Biden's agenda -- or whether Republicans will win a 50th seat and create some continued procedural friction as part of what they describe as a necessary check on the White House.
Nevada Sen. Catherine Cortez Masto's victory in her close race against Republican candidate Adam Laxalt secured a 50th Democratic seat assuring that, with the tie-breaking vote of Vice President Kamala Harris, Democrats would keep control regardless of what happens in Georgia.
But Democrats have stressed the importance of Tuesday's runoff race between Sen. Raphael Warnock and Republican rival Herschel Walker. That's because a 51-seat majority would make governing much easier than the current 50-50 split.
Republicans, at the same time, are looking to even the score with the Georgia midterms and to keep the chamber in its current power-sharing agreement.
"When Herschel [Walker] wins, we're gonna have a 50/50 Senate," Republican Senatorial Committee Chairman Rick Scott told reporters in Georgia last month. "Right now it'd be better to read 51, 52, 53. But by him winning, we will be able to block some bad legislation because it takes 51-plus to get this stuff done," Scott said.
Democrats are going all out to get to 51.
"It's obvious that 51 is better than 50," Senate Majority Leader Chuck Schumer said during a November appearance on CNN.
One big reason: judges.
Easier to confirm presidential nominees
Confirming judges who Biden nominates is a huge priority for Democratic leadership, especially after the Supreme Court, dominated by Republican-nominated justices, showed the might of the judiciary by overturning its past rulings on abortion rights earlier this year.
Democrats have been eager to counter the Supreme Court by filling the lower courts with more liberal justices -- and because confirming them is one of few things that can be done in the Senate with a simple majority, Senate Democrats have moved swiftly, confirming a record 84 Biden-nominated judges during the president's first two years in office.
But a 51-seat majority could allow Democrats to move judges through the Senate confirmation process even faster.
With 50 senators on each side, Senate committees are currently evenly split. Republicans can block Biden judicial nominees in the Judiciary Committee, forcing an additional vote on the Senate floor.
It amounts to a procedural hiccup, but it can gum up the Senate floor for days.
"That just slows the process down," Judiciary Chairman Dick Durbin has said. "If we had 51-49, it would be a much better situation. "
With 51 members, Democrats could clear nominees without this extra step, leaving them with more floor time to work on even more nominees or on other pieces of legislation they want to bring to a vote.
And the benefit of a 51-plus seat majority extends to other legislative priorities that deadlock in committee. Democrats would have the upper hand moving any of their legislation out of committee and to the floor for a vote.
Democrats would also have a bit more security if a Supreme Court vacancy should open in the next two years.
Supreme Court nominees
Had Senate GOP Leader Mitch McConnell taken control of the chamber, he was unclear about whether he would have allowed the Senate to even consider any of Biden's nominees for the highest court in the land, breaking with precedent.
Now that Schumer remains in charge, it's all but certain any vacancy could be filled with a Biden nominee, even if one Democrat decides to defect.
But 51 seats buys Democrats the freedom to have a single dissenter on all sorts of legislation, not just Supreme Court nominees. As such, Democratic leadership has been pushing for at least an additional seat in part because it would strip away the concentrated power that those on the left and right of the party have enjoyed during the last two years.
51 votes buys Democrats negotiating room
Over that time, the 50-seat majority has required Schumer to constantly corral his caucus, which spans from conservative Democrats like Sen. Joe Manchin, D-W.Va., all the way to progressive independents like Bernie Sanders, I-Vt. He could not afford a single dissenter.
This made Manchin highly influential in the 50-50 Senate. His decision to withhold support for Biden's cornerstone Build Back Better agenda tanked the bill last winter, with Democrats unable to move forward without unanimous support.
His move infuriated rank-and-file party members. But it ultimately bought him a direct seat at the negotiating table with Schumer, who was desperate to win his support. The two crafted the Inflation Reduction Act, which passed this summer, largely in one-on-one talks behind closed doors.
Sanders, for a period of time, threatened to sink a separate bill because it included a provision attached by Schumer to appease Manchin. As the two men locked horns, the government hurdled toward a shutdown. Manchin ultimately relented.
Schumer's wheeling and dealing with Manchin was necessitated by the evenly split Senate. But 51 votes buys wiggle room. And it has the potential to curtail Manchin's influence, or that of any other senator.
That doesn't mean there aren't other members, like Arizona Sen. Kyrsten Sinema, who could break with the party line and cause headaches. But it does give a bit more breathing room to Democratic leadership who will be eager to force Republicans to shoot down Biden policies in the lead up to the 2024 presidential election.
ABC News' Trish Turner contributed to this report.