Sen. Charles E. Schumer (D-N.Y.) woke up despondent the day after the 2016 elections, consoling himself and his daughters by singing the Shirelles’ 1961 classic: “Chapel bells are callin’ for everyone but-a me / But I don’t worry ’cause, /Mama said there’ll be days like this.”

Finally, after four years of battling President Trump and Senate Majority Leader Mitch McConnell (R-Ky.), Schumer heard the chapel bells calling his name. Democrats won two upsets in the Georgia runoff elections, giving Schumer a 50-member caucus.

When Kamala D. Harris is sworn in as vice president Jan. 20, she will become the tie-breaking vote in Democrats’ favor, giving Schumer control as majority leader and providing a huge boost to President-elect Joe Biden’s early agenda and confirmation of his Cabinet.

“It feels like a brand-new day,” Schumer said at a news conference just before noon Wednesday.

By 2 p.m., as the Senate began debating the baseless GOP claims of voter fraud in the presidential election, a pro-Trump mob had begun to breach the Capitol. An officer holding what appeared to be a machine gun stood between Schumer and McConnell, eyes trained on the Senate doors, ready to defend the chamber.

By 2:30 p.m., police ordered a full evacuation to secure rooms outside the Capitol, prompting an underground race through the basement complex. Officers on either side of Schumer held his shoulders to help race him along, finally breaking away from the group to take him to a different place for top congressional leaders.

Schumer and McConnell, joined by House Speaker Nancy Pelosi (D-Calif.) and House Minority Leader Kevin McCarthy (R-Calif.), received briefings and worked with law enforcement to determine safety inside the Capitol, eager to return to the building as a show of Democratic force.

At one point, McConnell finally turned to Schumer and congratulated him on the Democratic victory and becoming majority leader, according to a Democratic aide familiar with the conversation who spoke on the condition of anonymity to talk about the private exchange.

Now Schumer’s first days as majority leader have been thrown up in the air.

On Wednesday morning, he said his top priority was another pandemic relief package, including the bid for $2,000 checks to individuals.

By Thursday morning, Schumer issued a statement calling on Trump’s Cabinet to remove the president from office and, if not, saying Congress should rush an impeachment trial to try to oust him.

Under one scenario, a Senate trial would not begin until Jan. 19, Trump’s last full day as president and McConnell’s last day as majority leader. From there, Schumer would inherit an impeachment trial.

It would serve as an initial test of the likely push-and-pull that will dominate his tenure as majority leader — push hard to the left to please a liberal base that wants to see Trump punished, even if already gone from office, or work to have a speedy trial so he can begin to move quickly on to Biden’s Cabinet confirmations and his agenda.

Schumer will govern an evenly divided Senate without a single vote to spare, overseeing a caucus that runs the ideological gamut from Sen. Joe Manchin III (D-W.Va.) to Sen. Bernie Sanders (I-Vt.).

Schumer will have to balance that with one eye on his own reelection in 2022, as Empire State liberals search for a more liberal candidate to challenge his bid for a fifth Senate term — perhaps Rep. Alexandria Ocasio-Cortez (D-N.Y.), the rising star from the Bronx.

In the weeks leading up to the November election, when Democrats hoped for a convincing majority, Schumer repeatedly said “nothing is off the table” when pressed about ending 60-vote filibuster rules on legislation and expanding the Supreme Court. Democrats fell short on the original election night, but the Georgia races went to runoffs and opened up another avenue to a new razor-thin majority.

With Manchin and several other Democrats leery of abolishing filibuster rules, Schumer will have to work with Pelosi and Biden on a very narrow track to achieve their legislative goals, using parliamentary maneuvers to get around McConnell’s expected opposition to almost every agenda item.

Despite those long odds, no president has ever entered the Oval Office with so much Washington experience matched with a cordial, decades-long relationship with the House speaker and Senate majority leader.

Longtime friends and advisers say no one is better prepared for this balancing act than Schumer, whose old-school flip phone serves as the political nerve center for the caucus.

“He’s a master of caucus unity,” said Matt House, a former senior adviser in the Democratic leader’s office. “Being master of the modern Senate requires keeping the caucus together, and there is nobody better at that than Schumer. He works at it. His political ideology fits just right.”

Schumer, 70, has spent 40 years climbing the ranks of Congress, the longest tenure of anyone before rising to Senate majority leader.

He won his first House race in 1980, bonding with up-and-coming Democrats who chafed under the autocratic rule of veteran committee chairmen, a group that eventually included a young Pelosi.

In 1998, he knocked off a three-term Senate incumbent and honed an aggressive media approach, including holding weekly Sunday news conferences in New York to jump on issues that were gaining attention.

In 2005, Harry M. Reid (D-Nev.), then Senate minority leader, handed him full control of the Democratic Senatorial Campaign Committee, a four-year run in which Schumer built the 60-seate Senate majority that won passage of the Affordable Care Act, an overhaul of Wall Street laws and other victories for the Obama administration.

In early 2016, as he prepared to succeed the retiring Reid, Schumer asked Biden to be the top surrogate in Senate races, particularly in places like Indiana and Missouri, where other Democrats were not welcome.

On the 2016 election night, Schumer bolted from New York soon after the polls closed and his easy reelection was official, flying back to Senate Democratic campaign headquarters to celebrate with Reid and Biden.

As returns trickled in, the celebration was canceled. Trump won, and McConnell was still majority leader.

As minority leader, Schumer has kept his caucus together on every major vote the past four years. Some Democrats like Manchin supported occasional Trump initiatives or Supreme Court justices, but not once did their votes provide the margin of victory.

His leadership team runs from Manchin to Sen. Elizabeth Warren (D-Mass.), giving him constant insight into all corners of his caucus, but some rank-and-file Democrats forced an internal caucus debate about the top-down nature of leadership power after the November elections.

That initial gloom for Senate Democrats — not securing the majority despite Biden’s national victory margin of more than 7 million votes — gave way to an intense focus on the two Georgia runoffs, knowing a double victory in political overtime would give them a 50-50 split with Harris breaking the tie in their favor.

But no one planned a party.

Schumer spent Tuesday night at his home in Brooklyn with family. He called the Democratic candidates, Jon Ossoff and Raphael Warnock, at least three or four times each, assessing where their races stood.

Finally, around midnight, he realized it would finally be his turn to walk down the Senate aisle as the bells called his name: Majority Leader Schumer.

“Wow, who would’ve thought? As I said, this is not the path we chose to get here, but we’re here,” he told reporters Wednesday.

Two-and-a-half hours later, Schumer got pulled down another path not of his choosing, by his security detail trying to save him.

That path now sets up his first big test as majority leader.