Joe Biden’s path to victory in 2016

To understand the wrenching dilemma Vice President Joe Biden faces, just consider the events of Thursday.

Early that evening, a new CNN poll showed yet more erosion in support for Hillary Clinton. The former secretary of state is now for the first time under 40% in the Democratic race, leading Bernie Sanders 37% to 22%, with Biden right behind at 20%. Compare that to where this campaign started, with Clinton enjoying leads of more than 50 points over Biden, Sanders and the rest of the field. Back then, she appeared to be the most dominant non-incumbent presidential candidate in the modern era. Now, she seems at least potentially vulnerable. This is a race that is only getting more enticing to Biden, who at 72 years old knows this is his last opportunity to claim the job he’s coveted for decades.

But then, hours after the poll’s release, came Biden’s appearance on Stephen Colbert’s “Late Show.” Discussing the death this summer of his son Beau, Biden provided an arresting display of grief, one that surely gave millions of Americans new respect and admiration for the vice president. But it also demonstrated the degree to which Biden is still reeling from his latest family tragedy – something that, as he admitted during the interview, gives him real pause as he ponders a late-starting campaign.

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Make of it what you will. For now, Biden is officially undecided, and that posture has served him well this summer. While Clinton has endured withering media scrutiny and attacks from Republicans, Biden has remained above the fray, his popularity reaching new levels. But he can’t keep this up much longer. To run, he’ll need to raise big money and build a real organization, and deadlines for state primaries are now approaching. No one can say what exactly Biden the man is thinking. But there’s one key question for Biden the politician to ponder: Is there a path to victory?

The answer is yes. And actually, there are two. The first is the simplest and most dramatic: an all-out Clinton implosion that leads her to exit the race and prompts Democrats to rally around Biden. The second would require Biden to defeat Clinton during the primaries next year. This path is narrow, complicated and littered with contingencies.

What makes the situation so complicated is that the non-Clinton vote is now divided almost evenly between Biden and Sanders. If you add their support together, it would be enough to give Clinton a real run. But if it remains divided, the effect will be to boost Clinton. So Biden will need to eat substantially into Sanders’ support. But Biden, with his long history of championing the financial services industry, may not be a good match for those who have rallied behind Sanders’ call to take on “the billionaire class.”

Making matters more complicated is that the first two voting states, Iowa and New Hampshire, set up particularly well for Sanders. In both of them, he now leads Biden by substantial margins – and has even in some recent polls moved ahead of Clinton. It’s not impossible that Sanders could win both of these states, a development that would throw Clinton’s inevitability into instant doubt and set off waves of panic among the Democratic establishment. But it would be tough for Biden to capitalize on that panic if he finishes third in both states. Clinton would not quit the race and would then claim the South as her firewall. And Sanders, having knocked her off, would not be at risk of losing any of his supporters to Biden.

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What Biden would need, then, is to win one of the lead-off states. This would establish his legitimacy as a contender and weaken Clinton – and it would prevent Sanders from becoming an even bigger force. Then things would get interesting.

The Clinton team now claims the South as its firewall for demographic reasons. African-American voters, virtually invisible in Iowa and New Hampshire, will be a major force in the South Carolina primary and in the southern states that will vote as a bloc on March 1. And Clinton now enjoys massive support from black voters, with whom Sanders has struggled to gain traction. This type of southern firewall has protected embattled Democratic front-runners in the past, most notably Walter Mondale in 1984 and Bill Clinton in 1992, and right now it’s positioned to do the same for Hillary.

But if Biden can win in one of the first two states, then there is a way that he – unlike Sanders – could change the math in the South: an endorsement from his boss. Remember that eight years ago, the South was also supposed to be a firewall for Hillary Clinton. Throughout 2007, she enjoyed commanding leads over Barack Obama among black voters. But that all changed when Obama won Iowa and established that he really could win the nomination. That new credibility unleashed a decisive shift in support among black voters. In the South Carolina primary, which proved to be the turning point in the race, Obama won nearly 80% of the black vote.

As president, Obama has retained deep and unwavering support from black voters. Biden would be running as his loyal vice president, promising to protect and expand all of the achievements they have racked up together. Right now, Biden would get crushed in South Carolina. But what if he wins one of the early states, establishes his viability, and then receives an endorsement from the country’s first black president? Would that upend the math that Clinton is now relying on?

There are plenty of ifs in this scenario – maybe too many. And an obvious question is whether Obama would be willing to wade into the Democratic race at all, even for a vice president with whom he has grown so close personally. A Biden bid would be a long-shot, and the risk of an embarrassing third-place flameout would be real. But it’s not impossible to imagine him pulling it off. And that’s a lot more than anyone was saying six month ago.