Schumer, who was minority leader for four years, will be also be the first Jewish majority leader. And Ossoff and Warnock are the first Jewish and Black senators, respectively, to represent Georgia, which hasn’t sent a Democrat to the Senate in 20 years. Meanwhile, Padilla, who will replace Harris in the Senate, is the first Latino to represent California in the upper chamber.

Ossoff was accompanied by Sen. Cory Booker (D-N.J.), Padilla by Sen. Dianne Feinstein (D-Calif.) and Warnock by Sen. Tim Kaine (D-Va.).

Wednesday marked the first time in six years that Democrats have held the Senate majority and cemented full Democratic control of Washington for the first time in a decade.

While a Democratic Senate largely guarantees President Joe Biden will see his Cabinet nominees confirmed, the chamber’s 50-50 split, with Harris as the tie-breaker, leaves Democrats little room for internal dissent. The slim majority also reduces the odds that Democrats will scrap the legislative filibuster, meaning that at least 10 Republicans will need to work with Democrats on most legislation. Democrats, however, can use budget reconciliation procedures to pass some of their legislative priorities.

With an impeachment trial looming over the Senate, Democrats are vowing to both hold former President Donald Trump accountable for the Jan. 6 insurrection and move forward with another coronavirus relief package as well as Biden’s nominees. But that will require cooperation from Republicans, many of whom are resistant to impeachment as well as Biden’s agenda.

The Senate’s even split also means that Schumer and Senate Minority Leader Mitch McConnell (R-Ky.) will need to finalize a power-sharing agreement. McConnell is insisting that the agreement include a commitment to protect the legislative filibuster, which Democrats are expected to reject.

The power sharing agreement is otherwise likely to resemble the 2001 framework from former Senate leaders Trent Lott and Tom Dashchle, which split committee memberships and established that the party in control of the White House determined the Senate floor schedule. The leaders also have yet to finalize the parameters of the forthcoming impeachment trial, which can’t start until Speaker Nancy Pelosi sends the Senate the impeachment article charging Trump with inciting the Jan. 6 siege.

In addition to coronavirus relief, Schumer outlined a series of other priorities for Democrats in a letter to colleagues last week, including legislation related to immigration reform, climate change, health care, criminal justice reform and the tax code.

In his speech, Schumer vowed that the Senate "will do business differently" under him.

"This Senate will legislate," Schumer said. "It will be active, responsive, energetic and bold. And to my Republican colleagues, when and where we can, the Democratic majority will strive to make this important work bipartisan. The Senate works best when we work together."