Hillary Clinton and Bernie Sanders, second from left, and the other candidates took on gun control, Benghazi and other big issues at the first Democratic presidential debate of the 2016 race. (Sarah Parnass/The Washington Post)

For many Democrats, Tuesday night’s debate provided a renewed sense of optimism and confidence in their field’s leaders. For Republicans, it was yet another opportunity to cast that field as weak and controversy-ridden.

These dueling perspectives played on loop Wednesday — on the campaign trail, in cable news interviews and on various social media platforms. Most of the attention centered on Hillary Rodham Clinton, the Democratic frontrunner, and Sen. Bernie Sanders (I-Vt.), who has been gaining on her. The two dominated the debate and generated the most buzz on social media.

Speculation continued Wednesday over whether or not Vice President Biden will join the race — and whether that move could now be far more difficult for him. After weeks of weighing his 2016 decision, Biden is running out of room for delay, as filing deadlines loom.

“I just think there are going to be fewer people this morning waiting for someone to ride in and save the party than there were yesterday morning, because [Clinton] gave a very self-assured, powerful performance last night,” David Axelrod, the chief strategist for Barack Obama’s two presidential campaigns, told CNN on Wednesday morning.

Take a look at the issues discussed and exchanges between candidates.

Clinton had the most riding on this debate, one of several critical events that have made October a crucial inflection point for her campaign. Her campaign staff gushed about her performance Wednesday, releasing a video of her opening statement — during which she said that “finally, fathers will be able to say to their daughters, ‘You, too, can grow up to be president” — edited together with vintage photos of the candidate. Clinton planned to stay in Nevada on Wednesday, attending two campaign events later in the day — including her first official rally since her June announcement.

Several of Clinton’s Republican rivals said she escaped aggressive questioning, laying out potential follow-up questions. Former Florida governor Jeb Bush asked, “What?” after Clinton explained why her position on the Keystone pipeline seemed to change. As Clinton discussed foreign policy, Bush suggested this question: “Seriously?”

“If you think this country is on the wrong track, Hillary Clinton just told you she has no interest in changing direction,” Bush tweeted Tuesday night. “I sure will.”

Republican criticism of Clinton largely followed the same script it has for months, heavily focused on her use of a private e-mail server while she was secretary of state and her handling of the 2012 attack on the U.S. consulate in Benghazi.

Former Arkansas governor Mike Huckabee, who has battled the Clintons for decades, tweeted a series of criticisms of Clinton’s performance Wednesday, including this tweet: “If only @HillaryClinton was as passionate about protecting American diplomats as she is about blasting the GOP. #Benghazi.”

Republican frontrunner Donald Trump said Clinton “came out the winner” of the debate, partly because “it was a very kind debate, very gentle.”

At the first Democratic presidential debate of the 2016 election, former secretary of state Hillary Clinton said Sen. Bernie Sanders (I-Vt.) was not tough enough on guns. (CNN)

“They had to hit her hard, and they decided not to do that,” Trump said on ABC’s Good Morning America early Wednesday.

Trump was especially critical of Sanders, saying the senator should have raised questions about Clinton’s email management rather than defending her on the issue. Trump posted a video on his Instagram account on Wednesday that called for “a tough, strong leader” and stated that Sanders — shown in video footage looking confused at an event as Black Lives Matter activists interrupt him — is not the guy for the job. The brief video ends with this message on a black screen: “Bernie can’t even defend his microphone. How will he defend the country?”

Huckabee saved some of his most creative and controverisal tweets for Sanders, writing: “I trust @BernieSanders with my tax dollars like I trust a North Korean chef with my labrador!” and “@BernieSander’s free college Ponzi scheme would make Bernie Madoff blush.”

Sanders and his supporters seemed to ignore these attacks, instead celebrating that the candidate generated the most buzz on social media during the two-hour debate, capturing 43 percent of the chatter across various platforms, according to Zignal Labs. Clinton was in second place, at 33 percent.

Sanders delivered one of most quoted lines of the night, as Clinton responded to questions about her emails: “The American people are sick and tired of hearing about your damn e-mails,” Sanders said.

Jeff Weaver, Bernie Sanders’s campaign manager, said the comment was not planned — so he was surprised and delighted when he heard it.

“When we heard that line, the people who were watching with us, we went crazy,” campaign manager said Wednesday morning on CNN. “We had never heard that line before. It was fantastic, right?”

Sanders traveled from Las Vegas to Los Angeles on Wednesday to tape an episode of “Ellen” that will air on Thursday and attend a pair of fundraisers later in the day.

Although the spotlight continued to focus on Clinton and Sanders, the debate was an opportunity for three other Democratic candidates to introduce themselves to voters — former Maryland governor Martin O’Malley, former senator Jim Webb of Virginia, and former senator and governor Lincoln D. Chafee of Rhode Island.

Clinton and Sanders had cordially avoided criticizing each other on the campaign trail, but they were quick to challenge each other on the debate stage, often with surprisingly sharp and pointed language. They clashed over national security, the economy, big banks and gun-control policy in a spirited but largely civil exchange that underscored competing approaches to helping the middle class and leading the country.

The others on stage seemed more than happy to join, looking to give their lagging campaigns a boost before the biggest national audience they’ve had all year. In the race for social media buzz, Zignal Labs put Webb in third place, earning more mentions than both Chafee and O’Malley combined.

“It felt great to finally have a debate,” O’Malley told CNN on Wednesday morning. “I think for the first time people viewing from across the country saw that there were more than two candidates running for president in the Democratic Party.”

Chafee struggled at times during the debate. When questioned about his 1999 vote to repeal the Glass-Steagall Act — which then allowed commerical banks to engage in investment banking — Chafee said this was his “very first vote” after being appointed to office and came soon after his father died. When moderator Anderson Cooper pushed Chafee to better explain himself, the candidate said: “I think you’re being a little rough.”

In a race involving hundreds of millions of dollars, Chafee has only raised about $30,000, he said in an interview with CNN’s Wolf Blitzer on Wednesday afternoon. His struggle to register in early polls prompted Blitzer to ask: “So at what point will you drop out?”

Chafee said he’s the only candidate heavily focused on protesting war, so he feels the need to stay in the race.

“I’m in it for as long as I can raise these issues,” Chafee said. “They’re important, and I feel strongly about that.”

Katie Zezima, James Hohmann, Dan Balz, Anne Gearan, John Wagner and Philip Rucker contributed to this report.