LAS VEGAS — For Bernie Sanders Bernie SandersButtigieg stands in as Pence for Harris's debate practice Bernie Sanders warns of 'nightmare scenario' if Trump refuses election results Harris joins women's voter mobilization event also featuring Pelosi, Gloria Steinem, Jane Fonda MORE (I), the big moment has arrived.

When the left-wing senator from Vermont strides to his lectern in the sumptuous Wynn Las Vegas hotel and casino on Tuesday evening, he will be before the biggest TV audience of his life. He will also be side-by-side with the Democratic front-runner for the presidency in 2016 he hopes to topple, Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE.

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But can he make the most of the opportunity?

“Most of Democratic America, and certainly independent America, has never really heard or seen Bernie Sanders,” said Tobe Berkovitz, a Boston University professor who specializes in political communications. “How will he play, in terms of both his socialist-liberalism as well as his New York-Burlington persona?”

If the two-hour encounter goes well for Sanders, it could create more momentum for his unexpectedly fierce challenge to Clinton. He is already ahead in the polls in New Hampshire, competitive in Iowa, and whittling away at the former secretary of State’s lead in national polls.

On the other hand, a misfire could place a ceiling on his hopes, see Clinton reassert her dominance and even give an opening to otherwise overlooked Democratic candidates such as former Maryland Gov. Martin O’Malley, who will also be on the debate stage.

Sanders’s first goal, insiders say, needs to be a simple one: Let people know who he is.

“He still needs name recognition,” said Democratic strategist Brad Bannon. “Believe it or not, there are a lot of people out there, even among Democratic primary voters, who don’t know who Bernie Sanders is. Everybody knows who Hillary is.”

Aides to Sanders agree.

Tad Devine, a senior adviser to the Vermont senator, who has been in Congress since 1991, said that Sanders’s primary objective would be “to introduce himself to a much broader audience” and that his team was seeing the debate as “his first opportunity to talk to such a large number of people all at once.”

Sanders has attracted huge crowds during the campaign, and there are no signs that his appeal is dimming. On Oct. 3, he drew an estimated 20,000 people to an event in Boston.

But the viewing audience for the debate will be of a different scale. Approximately 24 million people watched the first GOP debate of the cycle, on Fox News in August, and around 23 million tuned in for the second Republican clash, on CNN last month. Tuesday night’s Democratic debate will be on CNN.

The biggest question for many political observers is how aggressively Sanders will go after Clinton. While he insists that he does not want to personalize the campaign, he'll want to draw the sharpest possible contrasts with Clinton, a task made more difficult by her accelerating shift to the left.

Just last week, Clinton announced her opposition to the Trans-Pacific Trade partnership, or TPP.

In the wake of that decision, Sanders told reporters, “I am delighted that Secretary Clinton is on board in opposition to the TPP. To be very frank with you, it would have been more helpful to have her on board a few months ago.”

Devine insisted that Sanders would “draw distinctions, for sure, but Bernie is not there to turn on everybody on the stage. His style of campaigning has not been to attack people. There are legitimate issues, but he is not out there trying to indict anybody.”

Notably, however, when asked about the issues Sanders was likely to highlight, Devine emphasized the role of money in U.S. politics in general, and the use of super-PACs in particular. The main super-PAC supporting Clinton, Priorities USA Action, has raised more than $15 million so far this cycle, according to the Center for Responsive Politics.

Still, attacking the role of money in politics is one thing — assailing Clinton over the email controversy that has roiled her campaign is quite another, and it is an issue that almost everyone expects Sanders to avoid.

“I doubt if he wants to get into the mud on the emails or Benghazi,” said Berkovitz. “Why should he spend his capital on that, anyways, when the media and Republicans are going to keep those subjects in the news?”

There are dangers for Sanders in taking the high road, however. One is that he could be put on the defensive by Clinton, who has been an effective debater throughout much of her career and could draw attention to issues where Sanders is not as liberal as much of his base, such as gun control.

The other possibility is that the other three candidates on the stage — O’Malley, former Sen. Jim Webb (D-Va.) and former Rhode Island Gov. Lincoln Chafee — could seize the opportunity to take on Clinton more aggressively, or even throw some sharp elbows in Sanders’s direction.

The other candidates “will have to be more aggressive because this may be their chance — ‘chance,’ singular — to be in the spotlight. I think the O’Malley people look at the race and they see lots of voters who are looking for an alternative to Hillary Clinton. So what they want to do is take down Bernie Sanders,” Bannon said.

One way or another, it’s likely to be a memorable fight night in Las Vegas.