When the Senate reconvenes Tuesday for the first time since the Jan. 6 attack on the Capitol building, they’ll be returning to a Capitol complex that looks entirely different than how they left it: Closed roads, security checkpoints, a building lined in 7-foot fences that are topped with razor wire and patrolled by 20,000 National Guard members, many of whom are bunking in the office buildings.

But legislatively, lawmakers are also in for a change as they return to Washington for a week of nomination hearings, an anticipated change in party control, new legislative priorities and a looming impeachment trial.

When President-elect Joe Biden and Vice President-elect Kamala Harris are sworn into office on Wednesday, they’ll usher in a new period of total Democratic control in Washington, marked, in part, by the eventual passing of the Senate gavel from Republican Leader Mitch McConnell to Democratic Leader Chuck Schumer.

It is not yet entirely clear when Schumer will formally take control of the body. Democrats will control the chamber by the narrowest possible margin, only securing the majority with Harris as the tie-breaking vote. But first, all new senators will need to be sworn in before the change in leadership is formalized.

Several new Democratic members of the Senate have yet to be sworn in and the exact timing of that has not been firmed up.

Harris resigned her Senate position Monday, paving way for former California Attorney General Xavier Beccera to fill her role. Becerra also resigned his position Monday, so his swearing in could occur swiftly. A date for it has not been formally set.

The Rev. Rafael Warnock and Jon Ossoff will also need to be sworn in before Democrats can take control of the body, something which cannot be scheduled until the Georgia Secretary of State certifies their victories in their respective Senate runoff races held Jan. 5. Certification could occur after the inauguration.

Regardless, Schumer has rolled out a list of Democratic priorities aligning closely with those of Biden’s that he is expected to steer the Senate towards in the coming days.

Democrats key focus this week will be the expedient confirmation of key Biden administration appointments, particularly in areas of national security.

“We need people in office quickly,” Schumer said Sunday. “And I would hope that our Republican colleagues would join us in putting the secretary of defense, secretary of homeland security, secretary of state, attorney general and others in office ASAP. Given the crises in this country, we cannot wait.”

Already, the Biden administration will enter the White House lagging behind other administrations on key appointments, owing in part to the delay of some Republican-controlled committees in scheduling confirmation hearings.

President Donald Trump’s defense and homeland security secretaries were confirmed by the Senate the day he entered the White House. Six Cabinet positions were filled on the day President Barack Obama took the oath of office.

Key positions will be vacant when Biden takes the oath of office, though the the Senate has six nomination hearings for key positions scheduled for this week: Avril Haines to serve as director of national intelligence, Tony Blinken to serve as secretary of state, Janet Yellen to serve as secretary of treasury, Lloyd Austin to serve as defense secretary, Pete Buttigieg to serve as secretary of transportation, and Alejandro Mayorkas to serve as secretary of the department of homeland security.

Schumer has also said that a “first order of legislative business” upon his assumption of the gavel will be another round of COVID-19 relief. He’s thrown his support behind Biden’s $1.9 trillion relief proposal which includes additional direct payments to Americans, extends a temporary boost in unemployment benefits, a moratorium on evictions and foreclosures through September, and provides funding for testing, vaccinations, K-12 schools and more.

Democrats immediately rallied behind the Biden proposal.

Sen. Patty Murray, the top Democrat on the Senate Health Committee, called the package a “world of change from President Trump’s hands-off, head-in-the-sand approach.”

Republicans have been largely silent. The few who have weighed in on the package have scoffed at the price tag.

“Blasting out another $2 trillion in borrowed or printed money — when the ink on December’s $1 trillion aid bill is barely dry and much of the money is not yet spent — would be a colossal waste and economically harmful,” Sen. Pat Toomey, R-Pa., said.

This is familiar ground. Deadlock over the overall cost of the last COVID-19 relief package paralyzed the Senate for months last year. Even with slight majority control, at least 10 GOP members will need to join Democrats to make law.

Schumer’s ability to make progress on nominees or COVID-19 relief could potentially be slowed by the outstanding article of impeachment in the House.

The House impeached Trump on Wednesday for “incitement of insurrection” following the violent siege on the Capitol that left five people dead.

McConnell said in a statement that the Senate expects to hold a trial as soon as the House impeachment managers formally deliver the article to the Senate chamber. So far Pelosi has been mum on when she plans to trigger the trial.

Once the article is delivered, the Senate would need to come to an agreement to allow other business, like votes on nominees, to occur during hours that the trial is not ongoing. The standing rules of impeachment require the Senate to suspend other business while an impeachment trial is ongoing and for the Senate to convene for the trial six days a week at 1 p.m. until a verdict is reached. Consensus of the Senate is required to alter these rules.

Schumer said Sunday that Democrats are “working with our Republican colleagues to try to come up with a bifurcated plan.”

Biden has also spoken to McConnell about establishing a means for the trial to commence while the Senate addresses other business and has said this is his “hope and expectation.”

Logistics of the trial are further clouded by questions about the constitutionality of impeaching a president after he has left the White House. Several legal scholars have argued that the Senate has no authority to proceed after Biden is inaugurated and they’ve been joined in their argument by some Senate Republicans.

Sen. Lindsey Graham, R-S.C., wrote to Schumer on Sunday arguing that the Senate should vote to dismiss the article.

“Proceeding with the spectacle of impeachment of a former president is as unwise as it is unconstitutional,” Graham wrote. “The Senate’s attempt to disqualify a President from future office who is no longer in office, would be an unconstitutional act of political vengeance, not a righteous constitutional act to protect the Nation by removal of an incumbent president.”

There’s been no indication that such a vote will occur at this time.