LAS VEGAS — For those Democrats who are Ridin’ with Biden and hoping Vice President Joe Biden’s White House ambitions will kick into gear, the road just got a lot steeper.
Hillary Clinton’s polished, upbeat performance at the first Democratic debate Tuesday night reinforced her front-runner status and calmed the nerves of top party officials, some of whom had grown worried about her wobbly campaigning over the summer.
Clinton’s campaign tried to drive home the point after the debate, saying the candidate is ready for the challenge if Biden chooses to get in.
“We’ve come to the point where he has to decide, and if he’s going to get in, we’re going to run our race. And you saw that race being run [at the debate],” said Clinton campaign chairman John Podesta. “She hit it out of the park, and she looked presidential.”
The former secretary of state’s backers were careful to toe what’s become the Clinton campaign line on Biden: they respect him and the process he is going through to determine whether to jump into the race. Still, Podesta slipped into past tense talking about the Biden threat. “I don’t think it was ever about her, it was about him,” Podesta said.
A high-ranking Democratic Party official, who is neutral in the race, said the debate instantly altered the landscape: “What changed is it makes it difficult for anyone who is challenging her strength to make the case. Anyone.”
Biden has skipped over a series of self-imposed deadlines to make up his mind about entering the race, but will come up against a hard one soon: Next month’s calendar includes a host of filing deadlines for early primary states, and some later states that are rich in delegates.
Biden praised all five Democratic candidates on the stage Tuesday night.
‘‘I was proud,’’ Biden said Wednesday. ‘‘I thought every one of those folks last night — my own prejudice — I thought they all did well.’’
The vice president did not respond to a reporter’s shouted question about when he’ll announce his decision, the Associated Press reported.
Biden supporters said they did not believe Clinton’s debate performance would affect Biden’s deliberations.
“She is a technically skilled debater,” said Larry Rasky, a Democratic political consultant in Massachusetts and close Biden confidant. “I don’t see that a lot changed. I can’t see anything that would impact his thinking.”
An outside group trying to draft Biden into the race also asserted the vice president would not be swayed.
“The vice president isn’t going to making his decision to run based on what he has seen during any debate or in response to any other candidate,’’ said Sarah Ford, a spokeswoman for the super PAC Draft Biden.
The group paid for gauzy pro-Biden ads to run on CNN Tuesday before the debate, spots that highlighted his support for the middle class.
The possibility of Biden entering the Democratic presidential contest has hung over the race since early August, causing intense scrutiny of the vice president’s every speech and his public schedule.
Biden has twice sought the White House, but halted his exploration of a third run when his eldest son became ill with brain cancer. Beau Biden died in May.
Joe Biden initially refused to talk to top aides about his political future. But toward the end of the summer he was more open about exploring a run, prompting close scrutiny of his speeches and public schedule.
Voices pushing Biden to get into the race grew louder as Clinton was dogged by a controversy over her use of a private e-mail server while she was secretary of state, and whether any classified material passed through it and was mishandled. The FBI took possession of her server and has launched an inquiry.
But on a night that Clinton needed to address that investigation, and calm nervous Democrats, she delivered.
Viewership of Tuesday night’s debate was huge, allowing Clinton to make a positive impression on a broader array of domestic and foreign policy issues. The two-hour debate attracted a record 15.3 million viewers for a Democratic primary debate.
She attempted to bat down questions about the e-mails, and then got what Podesta called an “assist” from Senator Bernie Sanders of Vermont, who delivered the most remembered line of the debate: “The American people are sick and tired of hearing about your damn e-mails!”
That thrilled the debate crowd at the Wynn Las Vegas hotel and helped foster the notion among Democratic faithful and pundits that, at least temporarily, Clinton may weather the storm around the e-mails and the still-simmering controversy over the fatal 2012 attack on the US mission in Benghazi, Libya, when she was secretary of state.
“The assumption about Biden was that Hillary was going to fold under the force of Benghazi and the e-mails and the attacks,” the Rev. Jesse Jackson, the civil rights activist and former Democratic presidential candidate who has not endorsed anyone in this race, said to reporters in the postdebate “spin room.’’ “That’s less likely to happen. So the reasoning of having him in as a safety net has probably diminished.”
Still, Clinton was bracketed by untested candidates, and her experience in high-profile debates gave her a big advantage. Sanders appeared unprepared for an obvious line of attack from Clinton: his mixed record on gun legislation.
Clinton laughed and shook Sanders’ hand when he declared that the e-mail flap was not worth further scrutiny.
Sanders’ team said his decision to give Clinton a pass on the e-mail controversy was unscripted, although the campaign immediately sent out a fund-raising e-mail with a clip of the exchange to supporters. His camp reported raising $1.3 million in small contributions within four hours of the debate.
Annie Linskey can be reached at Annie.Linskey@globe.com.