bernie-sanders.JPG

While Democratic presidential candidate Bernie Sanders is leading rival Hillary Clinton in recent Iowa and New Hampshire polls, a lot of things have to happen for him to win his party's nomination.

(AP Photo/Andrew Harnik)

COLUMBUS, Ohio--Bernie Sanders has surged in recent days, with polls showing he has a good shot of winning both the Iowa caucuses and New Hampshire primaries next month.

But the likelihood that the U.S. senator from Vermont will win the Democratic nomination over Hillary Clinton, while possible, is still unlikely, according to several political experts and analysts interviewed by cleveland.com.

For Sanders to become the Democratic nominee, they say, six things need to happen:

Mobile readers: We've divided this story into separate sections. You can hit "back" to return to this list.

A strong showing in Iowa and New Hampshire A tarnished Hillary Clinton Support from minorities Democratic superdelegates Turning enthusiasm into votes: A "black swan" election

1) A strong showing in Iowa and New Hampshire: Sanders first has to prove he's viable by either winning or finishing a very close second in next month's Iowa caucuses and New Hampshire primary.

If he does that, it will cause a frenzy of much-needed coverage from the media, which are tired of Donald Trump and eager for a competitive Democratic primary, said James Morone, a political science professor at Brown University.

"Sanders is such a long shot that he needs spectacular media attention," Morone said.

Sanders will need the favorable publicity because he'll face a round of much tougher contests in the following days -- starting with Nevada and South Carolina, where recent polls show Clinton with leads of 23 percentage points and 40 percentage points, respectively.

2) A tarnished Hillary Clinton: Several political analysts said it won't be enough for Sanders to attract undecided voters - to win, he will need large numbers of Clinton voters to defect to his side.

For that to happen, Clinton would have to suffer some sort of new, major scandal or commit a fatal misstep, said Nathan Gonzales, editor of The Rothenberg & Gonzales Political Report, a non-partisan political newsletter.

"In order for Sanders to win, it would have to be a combination of Clinton tanking and Sanders rising," he said.

If Sanders wins, it will be at least in part because many Democrats - particularly younger voters - believe he is more genuine and trustworthy than Clinton, said Baldwin Wallace University political scientist Thomas Sutton.

"It's not about any particular decision or policies," Sutton said. "It's a character issue."

3) Support from minorities: Sanders has struggled to gain support among black and Latino voters. A recent NBC News/SurveyMonkey nationwide poll showed Clinton leading Sanders among African Americans (63 percent to 20 percent) and among Hispanics (54 percent to 33 percent).

The crowds that have turned out to Sanders campaign events have been overwhelmingly white. He was also shouted down and forced off a stage by Black Lives Matter activists last August in Seattle.

Clinton, meanwhile, has a strong base of support from black voters, possibly because of lingering popularity for her husband, ex-President Bill Clinton, or because, as a group, they tend to back establishment candidates.

While New Hampshire and Iowa had the second- and third-highest share of white liberal voters, respectively, of any state during the 2008 Democratic primary, more than 70 percent of the states holding contests through March 1 have Democratic electorates that were at least 20 percent non-white as of 2008, according to a University of Virginia study. In three of those states - Alabama, Georgia, and Texas - a majority of Democratic primary voters in 2008 were racial minorities.

Sanders has been working to win black voters' support, tailoring messages to them about economic inequality and social justice. Last week, he launched a tour of historically black colleges and universities.

"When the African-American community becomes familiar with my Congressional record and with our agenda, and with our views on the economy, and criminal justice -- just as the general population has become more supportive, so will the African-American community, so will the Latino community," Sanders said during Sunday's Democratic debate.

4) Democratic superdelegates: About 30 percent of the 2,382 votes needed to win the Democratic presidential nomination are held by so-called "superdelegates" - more than 700 party leaders and officeholders who are not elected and can support any candidate they want. A November survey found that 359 superdelegates planned to vote for Clinton, while just 8 said they are backing Sanders.

Of course, the superdelegates could shift their support to Sanders by the time the convention is held in late July. But as most superdelegates are old-school party stalwarts, they won't be swayed by emotional arguments, said Morone. To win them over, he said, Sanders will need to keep winning state primaries to convince them he's the best Democratic candidate to run in November.

5) Turning enthusiasm into votes: That means building a get-out-the-vote operation in states across the country, not just Iowa and New Hampshire, said Jim Thurber, a political scientist at American University. In particular, Thurber said, Sanders has won support among young voters and some labor groups.

Sanders will also get help from outside groups, including MoveOn.org, a liberal grassroots organization with 8 million members nationwide that is helping his campaign to organize in Iowa and New Hampshire.

Ben Wikler, MoveOn.org's Washington, D.C. director, said Sanders' campaign against economic inequality has struck a chord with millions of Americans.

Such a message, he said, "can get people to turn out and vote and volunteer and get engaged and donate again and again who might not otherwise do so."

So far, that's happened. Sanders raised $73 million last year from a record 2.3 million donations. Clinton raised a total of $112 million in 2015.

But Adam Seth Levine, a political science professor at Cornell University, said Sanders is starting to shift his rhetoric from economic inequality (asking why a select few are so rich) to economic insecurity (questioning why so many aren't better off).

Such a shift will likely backfire on Sanders, Levine said. His research has found that when candidates convince people they are threatened economically, their supporters become fearful and donate less money and time to the candidate's campaign.

While Clinton has also campaigned on issues like health-care costs and escalating college costs, she is at less risk because she attracts far more wealthy donors who don't feel scared to open their checkbook, Levine said.

6) A "black swan" election: Conventional wisdom holds that Sanders, a self-proclaimed democratic socialist, is too liberal to be electable, said Ken Mayer, a political science professor at the University of Wisconsin at Madison.

But there are signs that this might not be a conventional election year. Americans are becoming increasingly frustrated with government, Mayer said, and are looking at political outsiders such as Sanders and Trump on the Republican side.

"There is a widespread sentiment out there that the system is broken, and someone like Sanders is better positioned to tap into that," Mayer said.

Elections that have surprising and unforeseen outcomes are known as "black swans," said Morone. While Morone said he doesn't believe such an election will happen this year, he noted that "no one saw Trump coming."

If there is a "black swan" election in 2016, he said, it will be because of voters' discontent over economic inequality, concerns about another economic recession, and strong feelings about immigration policy.

And if both Trump and Sanders are nominated, Morone added, "political scientists will have to throw out their playbooks."