Rep. Chris Van Hollen (D-Md.) cruised into the U.S. Senate on Tuesday, winning his bid to succeed five-term powerhouse Barbara A. Mikulski and allowing Maryland Democrats — for one night at least — to forget the humiliating loss of the governor’s mansion two years ago.

His victory over Del. Kathy Szeliga (R) — by more than 20 points — makes him the state’s first senator from the D.C. suburbs in a century. It was part of a big blue night in the deeply Democratic state, where Hillary Clinton easily beat Republican Donald Trump to claim the state’s 10 electoral votes.

The party kept its hold on seven of Maryland’s eight congressional districts, adding two new faces on a day when balloting was marred by lengthy waits and technical issues. Long lines in Baltimore City kept the polls there open well past the scheduled 8 p.m. closing time, delaying reporting of statewide results on the Board of Elections website.

State Sen. Jamie Raskin (D) claimed Van Hollen’s District 8 congressional seat, beating Republican Dan Cox by about 25 points. Former lieutenant governor Anthony Brown revived a political career that appeared over after his 2014 gubernatorial loss, defeating Republican George McDermott by a better than 2-to-1 margin to capture the seat being vacated by Rep. Donna F. Edwards.

Rep. Chris Van Hollen takes a selfie with friend and neighbor, Maria Recio, of Kensington at his precinct, Temple Emanuel. (Sarah L. Voisin/The Washington Post)

“Isn’t it great to be back?” Brown said to a crowd of Democrats at a victory party in Silver Spring. “Together we’ve had our successes, and we’ve had our shortcomings.”

In the 6th Congressional District, which stretches from Montgomery County through western Maryland, Rep. John Delaney (D) turned back a well-financed challenge from defense consultant Amie Hoeber to win a third term, winning by double digits.

Maryland’s five other incumbent House members — Rep. Andy Harris (R), and Democrats C.A. Dutch Ruppersberger, John Sarbanes, Steny H. Hoyer and Elijah E. Cummings — all won reelection.

State Sen. Catherine E. Pugh (D) will succeed outgoing Baltimore Mayor Stephanie Rawlings-Blake (D), despite a last-minute write-in effort by former mayor Sheila Dixon (D).

Van Hollen, 57, a consummate insider and policy wonk who rose quickly in House leadership ranks over his seven terms, campaigned hard this fall after a bruising primary against Edwards. He presented himself as a negotiator comfortable working across the aisle and highlighted his roles in Wall Street reform and passage of the Affordable Care Act.

Szeliga, 55, the minority whip in Maryland’s House, played down a staunchly conservative voting record that included opposition to stricter gun control, same-sex marriage and an increased state minimum wage. She tried to gain traction by focusing on Van Hollen’s support for the Obama administration’s Iran nuclear deal — and his support of Clinton.

Mafiz Chowdhury, a Democrat who lives in Potomac, said Tuesday he voted for Van Hollen after meeting him a couple of times. Chowdhury said liked that Van Hollen, who lives in Kensington, was “upfront and honest” during his time in the House.

“He’s a very people-oriented person,” Chowdhury, 51, said after voting at Cold Spring Elementary School in Potomac. “He seems to have the intention to help people, and I fell for that.”

Van Hollen also won votes from Trump supporters in more conservative parts of the state. In Edgemere, a blue-collar town just east of Baltimore, Shannon Nelson voted for the billionaire but backed Van Hollen over Szeliga because of the Democrat’s experience and union endorsements.

“I’m concerned about keeping my job and providing for my children through college,” the 32-year-old Republican longshoreman said.

At the Democrats’ victory party in Silver Spring on Tuesday night, Van Hollen took the stage at about 10:30 p.m. and announced he had received a call from Szeliga and thanked her.

“I am truly humbled, and it is time for all of us to get to work,” he told the crowd at the Tommy Douglas Conference Center.

Szeliga, a state delegate representing Baltimore County, took the stage at the BWI Marriott with a beaming smile, flanked mostly by family.

“There is a movement for change, and I’m going to continue to fight for you,” she said. “I’m going to continue to carry the banner for us and for our ideas.”

Van Hollen was the choice of the Democratic establishment in the Democratic primary, which exposed racial and gender fissures within the party.

Edwards, a former community activist and a single mother, was a standard-bearer for the party’s progressive wing as she sought to become Maryland’s first African American senator. She attacked Van Hollen as a creature of Beltway culture whose ties to Wall Street and past support for free-trade agreements put him out of touch with struggling voters.

Tensions rose when the super PAC funded by Emily’s List, the abortion rights group that supports women candidates, threw more than $2 million behind Edwards despite Van Hollen’s steadfast voting record on reproductive rights. But her insurgency faltered in the final weeks.

The defeats of Szeliga and Hoeber, and the pending departures of Mikulski and Edwards, both Democrats, leaves Maryland with an all-male congressional delegation for the first time in more than 40 years.

Jennifer Lawless, an American University professor and director of the school’s Women & Politics Institute, said the immediate impact should be minimal because Van Hollen, Raskin and Brown are “card-carrying progressives.”

“It’s not a setback,” Lawless said. “I don’t think we take any hits in terms of feminist agenda or policy.” She noted that Edwards, District 8 candidate Kathleen Matthews and District 4 contender Del. Joseline Peña-Melnyk, all of whom lost in the Democratic primary in April, ran strong races.

Longer-term, Lawless said, the 2016 elections underscore the importance of encouraging and cultivating women to run at the local, state and national levels. While Hillary Clinton’s candidacy shattered a historic glass ceiling, research shows that further down the ballot, the number of women running for Senate and House seats has remained more or less flat in recent years.

Brown, 54, beat out a crowded Democratic primary field that included Peña-Melnyk and former Prince George’s state’s attorney Glenn F. Ivey, immediately becoming the overwhelming favorite to succeed Edwards in Congress. During the campaign, Brown shed his political handlers and invested $400,000 of his own money to tell voters a more personal story about his role as a father and husband.

“Sometimes in life you’re going to get knocked down,” Brown said after casting his ballot Tuesday morning. “And if you believe in what you are doing, you pick yourself up, your brush yourself off and you and you stay in the fight.”

Raskin, 53, a Takoma Park law professor, enjoyed the backing of virtually every major Democratic interest group in the state. He survived a nine-way primary that featured the heaviest self-funded congressional candidate ever, Potomac wine magnate David Trone. Trone spent $13.4 million of his own money to finish second, slightly ahead of former Marriott executive and news anchor Kathleen Matthews.

In both the primary and the general election campaigns, Raskin promised to pursue the kind of liberal agenda he set in Annapolis, including prison reform, a ban on assault weapons and an increased minimum wage.

“It is not my job to be in the political center; it is my job to be in the moral center,” Raskin told supporters Tuesday night. “When they call me a progressive, I say darn right, because at the heart of that word is progress, and if we aren’t making progress, what are we doing in politics?”

Delaney, a financial services entrepreneur listed as the third-wealthiest member of Congress in some surveys, was aiming for a strong win over Hoeber after nearly losing his seat in 2014 to conservative talk radio host Dan Bongino. Political professionals in the state said he needed an impressive victory to keep his options open for a possible challenge to Hogan in 2018.

Rebecca Lipscomb, a special-education consultant who describes herself as a Libertarian, said she voted for Delaney because Hoeber’s positions “aligned more with that of Trump’s.”

“I can’t support any candidate who is that discriminatory toward that many people,” the 35-year-old from Gaithersburg said.