Former Vice President Joe Biden is the early front-runner in the 2020 Democratic presidential race — for the moment, at least. He leads in national polls and most surveys of the early primaries and caucuses, but if Biden were to falter, he wouldn’t be the first early primary front-runner to come up short.

Curious to understand how other high-name-recognition early front-runners have fared, we looked at candidates who consistently led in the polls at the outset of the campaign yet failed to win their party’s nomination. And we found four candidates since 1972 who fit that bill. Some made strategic errors or had personal foibles that led to their downfall. Others got tripped up by not appreciating the power of the media in the primary process. In still other instances, unexpectedly strong opponents and the volatility of the primary calendar gave them trouble. And, for some, their views were simply out of touch with their primary electorate, which made them particularly vulnerable.

Let’s first rewind to the 1972 cycle. Sen. Ed Muskie had made an impression as the Democratic vice presidential nominee in 1968, and the press anointed him the party’s front-runner in 1972. And throughout 1971, Muskie led in the national polls (typically with percentages in the mid-to-high 20s). He also topped early surveys in New Hampshire, helped by the fact that he came from neighboring Maine.

But trouble lurked ahead of New Hampshire’s March 7 primary. Even though Muskie led in New Hampshire, trouble with the media and the “expectations game” helped short-circuit his campaign. Less than two weeks before the primary, William Loeb, the conservative publisher of the Manchester Union Leader, published a letter to the editor (later found to have been forged by Nixon allies) that claimed Muskie had laughed at an aide’s use of a slur to describe people of French-Canadian descent, which was particularly damaging as a sizable share of New Hampshirites have roots in Quebec. Loeb also published an editorial criticizing Muskie’s wife. Outraged, Muskie held a press conference in front of the Union Leader’s offices amidst a snowstorm. And though it’s impossible to be sure, Muskie appeared to cry — some said the moisture was melted snow — which upset his image as a calm and even-keeled leader. Muskie did win the New Hampshire primary just a few days later, capturing 46 percent of the vote, but it was seen as underwhelming — Muskie had polled as high as 65 percent in January; instead, Sen. George McGovern (the better-organized eventual Democratic nominee) came out as the narrative winner with a stronger-than-expected 37 percent. Following weak showings in four of the next five primaries, Muskie withdrew from the race on April 27.

Fast forward to the 1988 cycle, and former Colorado Sen. Gary Hart started as the early Democratic front-runner. In 1984, he had battled former Vice President Walter Mondale all the way to the party’s convention, making him the assumed next candidate in line for 1988. And even though Hart’s national polls in the first few months of 1987 mostly ranged from the low to high 30s, his real strength was in Iowa, where he typically polled north of 50 percent in early 1987 surveys.

But as the front-runner, Hart faced greater scrutiny. People had a lot of questions about his life before politics, but more troubling were rumors of marital infidelity. Hart invited reporters to follow him around because he had nothing to hide, so they did. And it all came crashing down when the Miami Herald staked out Hart’s D.C. apartment in early May 1987 and watched Donna Rice — not Hart’s wife — come and go from it. In the face of the ensuing scandal, Hart withdrew from the race on May 8. However, he then re-entered the race in December 1987 and even led in some polls. But by the time the first contests occurred in February 1988, Hart had faded, barely winning any support in either Iowa or New Hampshire. Hart hung around until Super Tuesday on March 8 but then dropped out of the race for the second and final time. Massachusetts Gov. Michael Dukakis would go on to win the Democratic nomination.

It would be another two decades before another early polling front-runner ran and failed. But as it turned out, two such candidates came along in the 2008 cycle — then-Sen. Hillary Clinton and former New York City Mayor Rudy Giuliani.

From the moment she launched her campaign in January 2007, Clinton held the top spot in national surveys, polling in the low 30s or higher, and she led most New Hampshire polls. But Clinton had a past Senate vote weighing her down: She had supported the use of military force in Iraq in 2002. The Iraq War had always been less popular among Democrats than Republicans, but Clinton probably didn’t think of her vote as a dealbreaker since Sen. John Kerry had also voted for the bill and he still won the Democratic nomination in 2004. But by 2007, the war had become more unpopular, especially among Democrats. And Clinton’s main opponent in the Democratic primary — Barack Obama — had opposed the conflict and used that stance to draw a contrast between him and Clinton. Obama also challenged Clinton in other ways, such as drumming up impressive fundraising totals and assembling a stronger grassroots organization. He was also better prepared to win the eventual slog for delegates.

So despite leading national polls by around 20 points and polling second in Iowa before the caucus on Jan. 3, Clinton finished third in Iowa behind Obama and John Edwards, and Obama then surged in the New Hampshire polls. But, surprisingly, Clinton won the Jan. 8 primary, and the lengthy 2008 nomination battle continued. However, Clinton trailed in the delegate game from February on and never caught Obama. Things that were out of her campaign’s control may have contributed to her eventual defeat, too. For instance, Florida and Michigan had shifted their primaries to January to compete with Iowa and New Hampshire, moves that broke party rules and resulted in the states losing their delegates to the convention. (They later got half their delegates back.) Clinton won the penalized primaries — though Obama didn’t appear on the ballot in Michigan — and observers wondered if Clinton might have won the nomination if Florida had voted later and counted fully. But instead, Clinton ended her campaign on June 7 and endorsed Obama.

On the other side of the aisle, Giuliani had become a popular political figure following the 9/11 terrorist attacks. And after launching his campaign in February 2007, he consistently led in national polls and was initially neck–and–neck with John McCain in New Hampshire. Unlike the other front-runners we’ve examined, Giuliani never consistently led polls in at least one of the two principal early states, which, as we’ll discuss in a moment, became a serious problem for him. But he did lead the national polls, and he set the pace in fundraising during 2007, showing his campaign’s potential.

Giuliani was sunk by a couple of forces. First and foremost, he wasn’t a great fit with the GOP electorate. For instance, he was pro-choice and had long favored gun control. Giuliani said he would appoint conservative judges and that he was open to Roe v. Wade being overturned, but it wasn’t an easy sell. While he polled well nationally, Giuliani was perceived as more moderate-to-liberal on social issues than most Republicans wanted the eventual nominee to be. On top of these challenges, his campaign erred by not focusing sufficiently on early-state organization and relying too heavily on costly direct mail and TV ads to build support. Giuliani also didn’t commit enough time to New Hampshire despite the fact that the Granite State was likely to view him more favorably than socially conservative Iowa. With Giuliani’s weakness in the early states, his campaign embraced a Florida-first strategy, hoping a strong performance there would boost him in the Super Tuesday contests the following week. Giuliani’s distant third-place result in Florida instead ended his bid. The former mayor withdrew from the race on Jan. 30 and endorsed McCain.

It’s still too early to know what will happen with Biden, as plenty of polling front-runners have gone on to win their party’s nomination. But these past elections are an important reminder that campaigns can go wrong for many reasons, some of which candidates can control and others they can’t. For Biden, how he presents himself and plans out his campaign over the next few months will be crucial to whether he ends up as a failed or successful early primary polling front-runner.

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