(CNN) Former Rhode Island Gov. Lincoln Chafee ended his long-shot bid for the 2016 Democratic presidential nomination, he announced Friday. 
 
 "As you know, I have been campaigning on a platform of Prosperity Through Peace," Chafee said at the DNC's annual Women's Leadership Forum in Washington. "But after much thought I have decided to end my campaign for president today. I would like to take this opportunity one last time to advocate for a chance be given to peace." 
 
 The Democrat declared his presidential campaign in June, shortly after announcing that he had formed an exploratory committee. 
 
 One of the reasons Chafee decided to drop out now: Hillary Clinton had "a good week," he said, one where former Virginia Sen. Jim Webb dropped out of the race, Vice President Joe Biden declined to run and she withstood hours of testimony on Capitol Hill. 
 
 "Obviously it was a good week for Secretary Clinton," Chafee told reporters after his speech. "She did well in the debates and then Senator Webb got out, Vice President Biden declined to join the race, she did well in the Benghazi hearing and Gov. Chafee got out of the race." 
 
 Read More ||||| Vice President Joe Biden hasn't said if he'll run for president, but if he decides by Tuesday, he will have a spot on the debate stage. Video provided by Newsy Newslook 
 
 Hillary Clinton speaks at an awards gala sponsored by the Congressional Hispanic Caucus Institute on Oct. 8 (Photo: Teresa Kroeger, Getty Images) 
 
 The only participant at the first Democratic debate of the 2016 presidential campaign with nothing to prove is Sheryl Crow, the singer slated to open the evening by singing the National Anthem. 
 
 But for Hillary Clinton, Bernie Sanders, Martin O'Malley, Jim Webb and Lincoln Chafee, the stakes in Las Vegas Tuesday are going to be high. The two Republican debates held so far — boosting neurosurgeon Ben Carson and former CEO Carly Fiorina into top GOP ranks — have demonstrated the impact the nationally televised forums can have to shape and reshape voters' impressions. 
 
 Here's a quick look at what each of the Democratic candidates needs to do. The debate, sponsored by CNN and moderated by Anderson Cooper, starts at 8:30 PM ET. 
 
 'HELLO, I'M HILLARY' 
 
 Since Hillary Clinton formally announced her campaign in April, she's seen her poll standings fall and the controversy over her use of a private email server while secretary of State heat up. After a quarter-century in national politics, she no longer has a chance to make a first impression, but the debate does offer an opportunity for her to explain who she is and why she's running. 
 
 "Whatever her message has been, it's been drowned out by emails and servers and the opposition," Democratic strategist Joe Trippi, a veteran of past presidential campaigns, said in an interview. ""This is a real chance for her to lay it out." 
 
 What analysts don't expect her to do is attack challenger Bernie Sanders, whose supporters she will need if and when she wins the nomination. "Frankly, both Sanders and Clinton need to communicate warmth," says Democratic pollster Margie Omero. In contrast to the confrontational back-and-forth of the Republican debates, she says, "we may be able to determine the winner by looking at which candidate smiled the most." 
 
 That's not to say Clinton won't be attacked by others, on issues ranging from her 2002 vote in favor of the Iraq war to her reversal last week to oppose the Trans-Pacific Partnership. "She has to be prepared to answer the inevitable flip-flop question," says political scientist Dante Scala of the University of New Hampshire. 
 
 Strategists say Clinton, who has been on the defensive for months, needs to project an open manner. "This is really about her not having a shield up," Trippi says. 
 
 Sen. Bernie Sanders of Vermont at the University of Colorado in Boulder on Oct. 10 (Photo: David R. Jennings, AP) 
 
 A PLAUSIBLE PRESIDENT 
 
 Vermont Sen. Bernie Sanders arrives at the debate in a stronger position than even some of his top strategists initially thought possible. He has become a hero to progressive voters and the chief challenger to Clinton, and he is now drawing bigger crowds, more enthusiasm and nearly as much money as she is. 
 
 Expanding his appeal beyond his liberal base is his next task. "It's enough to get you 25%, 30% of the vote — and you're done," Trippi warns. "If you can't broaden to moderate blue-collar Democrats, Catholic Democrats, to African Americans and Hispanics, you can't win the nomination." 
 
 When the debate ends, success for Sanders would be "that Democratic primary voters find a Sanders presidency plausible," says Scala, co-author of The Four Faces of the Republican Party, being published by Palgrave Pivot next month. "It's one thing to be a prophet in the wilderness. It's another to be presidential. That's Sanders' challenge." 
 
 Sanders says his message espousing economic equity is one that resonates with many voters, including those who may not consider themselves particularly liberal. But the cost of his proposals are jaw-dropping. A Wall Street Journal analysis calculated it at $18 trillion in new government spending over the next decade. 
 
 "The big issue he'll need an answer for is on guns," Omero predicts. Sanders has opposed some proposals to limit access to guns, a record he argues reflects the sentiments of his constituents. The mostly rural Green Mountain State has one of the highest rates of gun ownership in the country. 
 
 Martin O'Malley addresses the New Hampshire Democratic Party State Convention on Sept. 19 (Photo: Scott Eisen, Getty Images) 
 
 I'M STANDING RIGHT HERE 
 
 If Sanders arrives at the debate in a stronger position than expected, Martin O'Malley arrives in a weaker one. The former two-term governor of Maryland has campaigned hard but still barely registers in national polls. The RealClearPolitics average of recent surveys puts his support at less than 1%. 
 
 "For the first time, O'Malley is finally going to have an audience," Trippi says. O'Malley has been more willing than Sanders to go after Clinton on the email controversy and on her changes in position in recent weeks to oppose the Keystone XL Pipeline and the Pacific trade deal. O'Malley needs a breakthrough moment or an exchange during the debate that convinces Democratic voters to consider his candidacy. 
 
 Jim Webb at the Iowa State Fair on Aug. 13 (Photo: Justin Sullivan, Getty Images) 
 
 REMEMBER IRAQ 
 
 Former Virginia senator Jim Webb has been running a low-profile, low-budget campaign. But his centrist views and his blunt manner gives him the potential to challenge the contenders seen as more likely Democratic nominees. He supports construction of the Keystone XL Pipeline, for instance, and argues that President Obama wasn't tough enough in the Iran negotiations. He also cites his opposition to the invasion of Iraq as a key selling point, which means he is likely to force Clinton to defend or at least discuss her 2002 vote to authorize the military action when she was a senator from New York. That was the main issue Barack Obama used in challenging Clinton in the 2008 primary campaign — which he won. 
 
 Lincoln Chafee at the New Hampshire Democratic convention on Sept. 19 (Photo: Jim Cole, AP) 
 
 RHODE ISLAND RESUME 
 
 Lincoln Chafee has the broadest political experience of anyone running for president in 2016. The Rhode Islander has served as a mayor, U.S. senator and governor, and he's run for office as a Republican, then an independent, and now as a Democrat. "He seems like a decent fellow," Trippi offers. That said, Chafee's resume hasn't made him a particularly serious contender. In the debate, he needs the same sort of breakthrough moment as O'Malley and Webb, but analysts say his reserved manner may make it harder for him. 
 
 Read or Share this story: http://usat.ly/1RCgZlB ||||| Two hours on a live debate stage Tuesday should be ample time for the Democratic underdogs battling front-runner Hillary Clinton to make a beneficial impression on voters — or to acutely disappoint them, politics watchers say. 
 
 “The debates will alter the race,” said Stephanie Cutter, a Democratic strategist and top staffer in the President Obama’s 2012 re-election campaign. “Clinton will no longer be running against herself — the debates will force a choice, but only if she strongly stands by her positions, record and beliefs and doesn’t get pushed to the left by others.” 
 
 Nearly 23 million viewers tuned in for the last GOP debate, featuring the smash-mouth antics of Donald Trump and his rivals’ attempts to weaken him. Will the Democrats be able to engage as many people for their first debate, set to begin at 9 p.m. ET (coverage starts at 8:30) on Tuesday in Las Vegas? 
 
 “Hillary should appear in character as ‘Val,’ ” joked Tracy Sefl, a former senior adviser to Ready for Hillary, the super PAC that laid the groundwork for Clinton’s campaign. Clinton portrayed a bartender named Val in a recent Saturday Night Live sketch. 
 
 Those competing Tuesday are Clinton, a former secretary of State; Vermont U.S. Sen. Bernie Sanders, her closest rival in the polls; former Maryland governor Martin O’Malley; former Virginia senator Jim Webb; and former Rhode Island governor Lincoln Chafee. 
 
 Executives with debate host CNN have said they’ll squeeze in an extra podium for the still-deciding Joe Biden if the vice president files last-minute paperwork for a 2016 presidential bid before the debate begins. 
 
 CNN reported recently that the vice president was likely to skip the opening debate. Still, the Biden question mark adds drama, said Grant Woodard, an Iowa political operative and lawyer. 
 
 “If he is there,” Woodard said, “it will be one hell of a show.” 
 
 The debate comes as Sanders has closed the polling gap on Clinton in Iowa, where party caucuses kick off the nation’s presidential voting, and overtaken her in New Hampshire, home of the first primary. 
 
 Here are six things to watch for: 
 
 1. Steam from the Hillary grilling 
 
 If the CNN debate moderators treat this as their chance to grill Clinton on live TV instead of carrying out an actual debate where other candidates are allotted plenty of time to make their case, “Democrats will likely be frustrated,” said Pat Rynard, a former Democratic campaign staffer from Iowa. 
 
 2. The Biden shadow 
 
 Even if he’s not on the stage, “Joe is a real part of the debate,” said Democrat Patty Judge, a former Iowa lieutenant governor. 
 
 “Sadly,” added Rynard, “in terms of the media narrative, nothing in the debate may matter if Biden announces his intentions the next day and wipes out all the coverage. Hopefully that doesn’t happen, but it’s near when Biden has to make a decision for ballot purposes.” 
 
 3. Sanders’ fidelity to fixed talking points 
 
 The liberal messenger could miss an opportunity if he expounds only a dry, policy-heavy message, Democrats said. 
 
 “He really refuses to deviate much from his economic inequality shtick on the campaign trail — which, to be fair, is a very powerful message that has gotten him far,” said Rynard, who writes about presidential politics on the website Iowa Starting Line. “(But) debates tend to favor interaction and candidates quick on their toes who can give punchy responses.” 
 
 4. Two debates in one 
 
 One debate will likely be a policy contest between Clinton and Sanders, both of whom have declined to stray into personal attacks, observers said. 
 
 “She will continue to move herself to the left in order to appeal to undecideds and to those who are leaning to Sanders but not firmly in his camp,” Judge said of Clinton. “She will also try to continue to distance herself from the Obama administration to give herself room to take on Biden if he gets into the race.” 
 
 The second debate could feature hard swings from the low-polling contenders, especially O’Malley, who has gotten increasingly personal in drawing contrasts with Clinton. 
 
 Watch for gun control, trade, banks and foreign policy to take center stage, said Michael Cheney, a professor of communication and economics at the University of Illinois at Springfield. 
 
 5. O’Malley’s moment? 
 
 Many Democrats worry that Sanders’ “socialist” label and Clinton’s struggles with her email controversy would badly hinder them in the general election, Rynard said. 
 
 O’Malley has run a serious campaign and impressed Democrats who go see him. But he barely attracts national media coverage, and many voters haven’t noticed him yet. 
 
 Cutter said: “This is the last best chance for Martin O’Malley.” 
 
 O’Malley needs to pull votes from Sanders, she said. “If he doesn’t distinguish himself as the person more likely to achieve results for a progressive agenda, rather than just a protest,” Cutter said, “then he’s out.” 
 
 6. The invisible Democrats 
 
 It’s now or never for Webb and Chafee, neither of whom do any real campaigning, Rynard said. 
 
 “At this point, they’re just taking up space,” he said. 
 
 Democrats said they’re hesitant to take either candidate seriously when even low-polling GOP candidates such as Rick Santorum, Bobby Jindal and Lindsey Graham throw energy into reaching out to early state voters. 
 
 But debates are fertile ground for earning a bump in the polls, strategists noted. 
 
 “The best debaters,” Sefl said, “are those who don’t look like they rehearsed their one-liners thousands of times, and who know how to demonstrate command of the issues without being the annoying kid from class who always raised their hand to every question.”
– Lincoln Chafee is saying what everybody was thinking: He's out of the race for president. The former Rhode Island governor made it official Friday morning in an address to the Women's Leadership Forum. "As you know I have been campaigning on a platform of 'Prosperity Through Peace,'" he said, per CNN. "But after much thought I have decided to end my campaign for president today. I would like to take this opportunity one last time to advocate for a chance [to] be given to peace." Two big reasons he dropped out: He was somewhere between 0% and 1% in the polls, and he'd raised only $30,000, reports the New York Times. Unlike Jim Webb, Chafee isn't interested in an independent bid, and his departure leaves Hillary Clinton, Bernie Sanders, and Martin O'Malley in the Democratic contest. (Clinton seems only to have strengthened her campaign after Thursday's marathon grilling over Benghazi.)