Democratic presidential candidate Hillary Clinton says that becoming the nation's first female president would be "quite a change." She was asked how her presidency would differ from President Obama's. (CNN)

If Hillary Rodham Clinton wins the Democratic presidential nomination, her Republican opponents will not let her off so easy.

On Tuesday night in Las Vegas, Clinton faced a set of Democratic rivals who seemed to lack the skill — or the will — to challenge her about her record on foreign policy, her changes­ in position, her handling of government data on a private e-mail server, or her claim to be an “outsider” after two decades in national politics.

When the former secretary of state praised Libya — now a cauldron of chaos and Islamist militias — as “smart power at its best,” nobody scoffed. When she was challenged about her e-mail practices, a controversy that has concerned many voters, top rival Bernie Sanders actually stepped in to dismiss the question. Americans are “tired of hearing about” it, he said.

For a night, the Democratic primary looked like what it was supposed to be a year ago: a coronation. On stage stood one dominant candidate, surrounded by others with other goals that didn’t include actually taking her down.

For Clinton, this night was a win. But it wasn’t great preparation. If Clinton is the Democratic nominee, she will face a Republican candidate who sees the very things she talked about Tuesday — Libya, the e-mails and her closeness with President Obama — as weapons to use against her.

“She won’t be so lucky when it comes to me!” wrote GOP front-runner Donald Trump on Twitter, deriding Clinton’s opponents as “the B-team.”

Reed Galen, a Utah-based GOP strategist, said he imagined much of what Clinton said Tuesday night making its way into television spots to benefit Republican candidates next year.

“She was like a walking 30-second ad script,” Galen said. “Having such a weak field is such a double-edged sword for her. She doesn’t get challenged on that.”

While Clinton’s opponents tried to land some punches­ on her ties to Wall Street and her past support for the invasion of Iraq, it was clear that they had little stomach to attack her on some of the very areas where Republicans believe Clinton is weakest — namely her character or leadership.

The image that came through Tuesday night of a strong, confident Clinton left her camp proclaiming success. After a rocky summer of falling poll numbers and questions about her use of the private e-mail server to conduct State Department business, this night was focused largely on the issues Clinton wanted to focus on.

Her supporters suggested she had closed the door to a late entry to the race by Vice President Biden.

“I think that door is shut, locked, no air is getting through. There’s just no way,” said Democratic strategist Matt Bennett of Third Way, who is supporting Clinton. “I just don’t think there’s a path for him. The only path he had really was the bed-wetters who were worried about Hillary, and I don’t think they’re worried this morning. What this debate will do much more than anything else is calm everybody down.”

On Tuesday, the strongest jab from a Democratic rival might have been something that Sanders said to Clinton. But it was a gentle jab, at best, and not directly aimed at her.

It came after Clinton — trying to show her ability to take on Wall Street — told a story about visiting a group of bankers in New York in 2007, when it was clear that Wall Street was taking risky bets on mortgages and securities.

“I basically said, ‘Cut it out! Quit foreclosing on homes! Quit engaging in these kinds of speculative behaviors!’ ” Clinton said. At the time, she represented Wall Street itself, as a senator from New York.

The bankers did not cut it out, of course. The year after Clinton’s scolding, a cascade of huge losses­ on Wall Street helped lead to a financial crisis and a long-lasting recession.

Sanders responded with a rebuke — but one that attacked the system before it attacked his rival.

“Congress does not regulate Wall Street. Wall Street regulates Congress,” he said, as Clinton tried to protest that he was misquoting her. “And we have got to break off these banks. Going to them and saying, ‘Please, do the right thing,’ is kind of naive.”

At other times in the debate, Clinton seemed to set her rivals up for a counter­punch that never came — but would almost surely come from Republicans in a general election.

When asked about Libya, for example, she played into long-standing criticisms of her — that she is too much like Obama and partly responsible for a less-assertive foreign policy that critics deride as “leading from behind.”

“Our response, which I think was smart power at its best, is that the United States will not lead this,” she said. “We will provide essential, unique capabilities that we have, but the Europeans and the Arabs had to be first over the line.” She boasted that, after that intervention, Libyans had held their first free election since 1951.

What Clinton left out was what’s happened since. The country as fallen into chaos, divided by militias and colonized by the Islamic State.

Clinton alluded to Libya’s downfall in a single passive-voice sentence.

“Because of the Arab Spring, because of a lot of other things, there was turmoil to be followed,” she said.

Beginning Tuesday night, Republicans seemed stunned that Clinton would take this episode — which they believed was a low point of her career as secretary — and cast it as a high point.

“ ‘Smart power at its best’ Seriously?” former Florida governor Jeb Bush wrote on Twitter.

Another case in point: On Tuesday evening, Clinton was asked to list the enemies she was most proud of. She listed the National Rifle Association, the Iranian government and . . . Republicans.

Which might be true, but it doesn’t seem very bipartisan. At some point, a few months from now, Clinton hopes to be in a position where looking bipartisan is important.

On Wednesday, Republicans followed up with a fundraising appeal based on Clinton’s crack. Sign up as a Hillary enemy, the appeal said. All it takes is a donation to the Republicans.