Las Vegas (CNN) Hillary Clinton and Bernie Sanders have been circling each other on electability for days, knocking one another from afar over which candidate stands a better chance to beat Republicans in November's general.

On Wednesday night in Las Vegas, they made their cases with the other candidate mere feet away.

"I am proud to be running in a Democratic primary with my opponents. They have a lot of good ideas and we share a lot of the same values," Clinton said with Sanders sitting at a dinner table nearby. "But your choice in the caucus really matters. On February 20th you will begin the process of choosing a president who has what it takes to stand up to the Republicans, to make a real difference for American families."

She then added, digging her critique a little deeper, "A president who can get the job done and not just on a few issue, but on all the complex challenges we face."

The comment was not taken kindly by Sanders supporters, many of whom booed the former secretary of state at points during her speech.

Sanders, speaking after Clinton at the dinner, responded in kind, teeing up his comment on electability by saying he wanted to be "clear" and "a little bit political" in his comments.

"All of us want to make sure that we defeat right wing extremism, that we make certain that no Republicans become president of the United States, all of us are united that we are going to take back the Senate and that we are going to do well all over this country," Sanders said. "But let me be very clear: That result will not happen with establishment politics and establishment economics. The only way that Democrats win elections, is when we have a large voter turnout."

Sanders supporters - keyed into the back and forth on electability - jumped to their feet at this comment. Clinton supporters did not, in part because many of them left after their candidate had finished speaking.

Clinton and Sanders were the main events at the dinner, but all three Democratic candidates - including former Maryland Gov. Martin O'Malley - tried to court their party's faithful at the Nevada Democrats "Battle Born/Battleground" First in the West Caucus Dinner.

But O'Malley, despite a more polished speech than past Democratic events, was largely an afterthought. While Clinton and Sanders supporters sat on opposing sides of the room, challenging each other to who could chant louder, O'Malley didn't have a noticeable cheering section.

Photos: Who's running for president? Ted Cruz, Donald Trump, John Kasich, Hillary Clinton and Bernie Sanders, Hide Caption 1 of 6 Photos: Who's running for president?

"So, ladies and gentlemen, I am officially running for president of the United States, and we are going to make our country great again," Trump told the crowd at his announcement. Businessman Donald Trump announced June 16 at his Trump Tower in New York City that he is seeking the Republican presidential nomination. This ends more than two decades of flirting with the idea of running for the White House."So, ladies and gentlemen, I am officially running for president of the United States, and we are going to make our country great again," Trump told the crowd at his announcement. Hide Caption 2 of 6 Photos: Who's running for president?

"These are all of our stories," Cruz told the audience at Liberty University in Virginia. "These are who we are as Americans. And yet for so many Americans, the promise of America seems more and more distant." Sen. Ted Cruz of Texas has made a name for himself in the Senate, solidifying his brand as a conservative firebrand willing to take on the GOP's establishment. He announced he was seeking the Republican presidential nomination in a speech on March 23."These are all of our stories," Cruz told the audience at Liberty University in Virginia. "These are who we are as Americans. And yet for so many Americans, the promise of America seems more and more distant." Hide Caption 3 of 6 Photos: Who's running for president? Ohio Gov. John Kasich joined the Republican field July 21 as he formally announced his White House bid.

"I am here to ask you for your prayers, for your support ... because I have decided to run for president of the United States," Kasich told his kickoff rally at the Ohio State University. Hide Caption 4 of 6 Photos: Who's running for president?

"Everyday Americans need a champion, and I want to be that champion -- so you can do more than just get by -- you can get ahead. And stay ahead," she said in her announcement video. "Because when families are strong, America is strong. So I'm hitting the road to earn your vote, because it's your time. And I hope you'll join me on this journey." Hillary Clinton launched her presidential bid on April 12 through a video message on social media. The former first lady, senator and secretary of state is considered the front-runner among possible Democratic candidates."Everyday Americans need a champion, and I want to be that champion -- so you can do more than just get by -- you can get ahead. And stay ahead," she said in her announcement video. "Because when families are strong, America is strong. So I'm hitting the road to earn your vote, because it's your time. And I hope you'll join me on this journey." Hide Caption 5 of 6 Photos: Who's running for president?

"This great nation and its government belong to all of the people and not to a handful of billionaires, their super PACs and their lobbyists," Sanders said at a rally in Vermont on May 26. Sen. Bernie Sanders , an independent from Vermont who caucuses with Democrats, announced his run in an email to supporters on April 30. He has said the United States needs a "political revolution" of working-class Americans to take back control of the government from billionaires."This great nation and its government belong to all of the people and not to a handful of billionaires, their super PACs and their lobbyists," Sanders said at a rally in Vermont on May 26. Hide Caption 6 of 6

Divided into camps

The audience was largely made up of decided voters. Campaigns gave supporters tickets to to the event and supplied them with different cheering paraphernalia. Clinton's supporters waved their now-common blue glow sticks, while Sanders' backers blew air-horns and hummed into vuvuzelas, the horns that became known for their annoying buzz during the 2010 World Cup.

"That music is really beautiful," Sanders said sarcastically to his supporters, before motioning for them to tone it down.

The argument over whether Clinton or Sanders is most electable has been playing out for the last three days on the Democratic side of the presidential campaign.

Touring through New Hampshire and Iowa, Clinton stressed her experience and her ability to hit the ground running if she were to win in November. She also urged her supporters to think about what a Republican presidency would be like, and cast her self as the best Democrat to stop that possibility.

"Let me ask you all to think hard about this job that you are interviewing for," Clinton said Tuesday night in Council Bluffs. "Think hard about the people who are presenting themselves to you, their experience, their qualifications, their positions, but particularly for those of us who are Democrats, their electability."

This comments annoyed Sanders aides - and the candidate.

Michael Briggs, Sanders' spokesman, quickly issued a statement in response to Clinton that questioned her ability to generate enough excitement to beat someone like Republican frontrunner Donald Trump.

And when asked by CNN on Wednesday - before his dinner speech - whether he is more electable than Clinton, the senator bluntly said, "Yes," before explaining how he polls better than Clinton in certain head to head polls.

And the candidate's supporters have taken note, too.

When asked, a handful of Sanders supporters almost unanimously said they were confident in their candidate's electability, even if it wasn't a reason they were backing the Vermont senator.

"I doesn't concern me at all," Sean Dolstad, a graphic designed from Las Vegas, said bluntly, reflecting what many of his Sanders supporting brethren said on Wednesday.

Clinton supporters, on the other hand, said their candidate's electability was a top reason they were supporting her, especially given the state of the Republican field.

"It matters tremendously," said Linda Overbey, a union member from Las Vegas. "I want to win, because for me, Donald Trump is a moron."