When was the last time the House and Senate were controlled by the same party?

Control of Congress

Barack Obama began his first term with full Democratic control. The 2009-11 Congress passed some of his signature policy achievements including the Affordable Care Act, an aggressive economic stimulus package and the Dodd-Frank financial reforms.

Mr. Obama was also able to protect two liberal seats on the Supreme Court with the appointments of Sonia Sotomayor and Elena Kagan in 2009 and 2010, respectively.

The Republicans went 40 years between 1955 and 1995 without ever controlling the House of Representatives but have made inroads in the last two decades.

Two-party representation at the start of each Congress

Democrats

Republicans

Tie

President

Party

Senate

House

Obama's first term

Democratic majorities in the 111th Congress, 2009-11

With strong majorities in both the Senate and House, Congress passed the Affordable Care Act, an aggressive economic stimulus package and the Dodd-Frank financial reforms.

Narrow majorities under George W. Bush

Republican majorities in the 108th and 109th Congresses, 2003-07

With narrow Senate majorities, Congress debated and approved the invasion of Iraq, passed tax cuts and approved aid in the aftermath of Hurricane Katrina.

Clinton's first term

Democratic majorities in the 103rd Congress, 1993-95

With strong majorities in the House and Senate, Congress passed the Family and Medical Leave Act and transformed trade relationships through Nafta and other reforms on tarrifs and trade.

The Carter years

Democratic majorities in the 95th and 96th Congresses, 1977-81

Congress under Jimmy Carter created the cabinet-level departments of Energy and Education.

The Kennedy and Johnson years

Democratic majorities in the 87th to 90th Congresses, 1961-69

A coalition of Northern and Southern Democrats held the House of Representatives for 40 years beginning in 1955 and held both chambers of Congress for most of the 1960s. Many of the social programs laid out in Lyndon Johnson’s ‘Great Society,’ were passed in the 89th Congress, including Medicare and Medicaid, sweeping civil rights protections, education reforms and environmental protections.

As the prospect of a divided Congress looms, many people have turned to Google in a frantic search for answers about what, exactly, the midterm election results will mean.

Who has more power: the House of Representatives or the Senate? What does the House control? What is the difference between the House and Senate?

So here is our attempt at a quick civics lesson. (It’s late, though, and we’re tired, so catchy “Schoolhouse Rock” jingles are not included.)

The House of Representatives

The House consists of 435 representatives who are each elected to a two-year term. The number of representatives per state is proportionate to the state’s population, and each representative serves his or her district.

Like the Senate, the House is responsible for introducing bills and amendments, and members of both bodies serve on committees — such as those for the budget and the judiciary.

The House has the power to initiate impeachment proceedings for government officials, and it is the chamber that introduces spending bills, giving it greater sway over the power of the purse.

With a Democratic majority, the House will have the opportunity to introduce bills that could force senators to make a decision that could hurt their favor with voters.

“It’s a very alluring prospect for Democrats now to be able to put together bills which enjoy a lot of public support,” said Ross Baker, a professor of American politics at Rutgers University. “And then send it to the Senate to reject them.”

The Senate

The Senate is often considered a more prestigious body, in part because there are far fewer senators than representatives, but also because the Constitution gives the group unique powers.

There are 100 senators in total, two per state. Each is elected to a six-year term.

George Washington is said to have explained the purpose of the Senate as to be more deliberative than the House: “We pour legislation into the Senate saucer to cool it.”

The Constitution gives the Senate the power to approve presidential nominations, including Supreme Court justices. Senators are also tasked with approving treaties with foreign countries.

The Senate has a long history of closely watched investigative hearings. A Senate committee investigated the Watergate scandal in the 1970s, for example, as well as allegations of sexual harassment against Justice Clarence Thomas in the 1990s.

Though impeachment proceedings begin in the House, the matter is then sent to the Senate, whose chambers act as a courtroom for the trial. The Senate has the sole power to conduct impeachment trials, essentially serving as the jury, as it did when it acquitted President Bill Clinton in 1999.

At least two-thirds of senators have to find the president guilty to remove him from office.

Which body has more power?

Although the Senate and the House have similar responsibilities to provide government oversight, the founding fathers gave them certain specialties, said Mr. Baker, the Rutgers professor.

“They have very distinct and separate functions to play,” he said. “In the Senate, it’s nominations and treaties, and in the House, it’s taxes and spending.”

Leading up to the midterm elections, House Democrats were preparing for an onslaught of hearings, subpoenas and investigations into nearly every corner of the Trump administration. The Democrat in line to be chairman of the Judiciary Committee also promised to open an investigation into accusations of sexual misconduct and perjury against Justice Brett M. Kavanaugh if the Democrats won a House majority.

President Trump has leveraged the Republican majority in the Senate to remake the courts. Mr. Trump came into office with more than 100 judicial vacancies; relaxed Senate rules on confirmations have allowed him to fill them quickly. So far, he has filled at least 60 seats on the federal district courts, appeals courts and the Supreme Court. With the Senate now even more solidly under Republican control, additional appointments are likely to come.

In terms of presidential succession, the speaker of the House is second in line, after the vice president. The president pro tempore of the Senate follows after the speaker.

But on perhaps the biggest issue — that of impeachment — the outlook remains largely unchanged.

With a Republican majority in the Senate, it is unlikely that the House Democrats would try to impeach Mr. Trump, barring big developments in the special counsel’s investigation or elsewhere. They’d never win the case in the Senate.