McGovern was a minor candidate in 1968. The young peoples' candidate was Eugene "Clean Gene" McCarthy.
The important thing to keep in mind, though, is that Sanders carries substantially more support than either of them.
Furthermore, as Matt Karp writes;
"Generally, however, the “electability” argument skips past Clinton and concentrates on Sanders. And here the case against Sanders divides into three general paths — one, guided by historical analogy; another, driven by pundit fears and fantasies; and a third, oriented around voter ideology and demographics. None are persuasive.
The most common way to dismiss Sanders is to lump him in with previous progressives battered by conservatives in general elections — usually Mondale in 1984 or George McGovern in 1972. “The early enthusiasm for Sanders reminds me of the McGovern and Mondale races, where two good men were only able to win one state each in their presidential campaigns,” former Louisiana senator John Breaux told the New York Times in January.
The logic of this analogy turns on the idea that McGovern and Mondale both lost for the simple reason that they were too liberal for American voters. The first rebuttal is almost too obvious to spell out: the 2016 electorate looks nothing like the 1972 or 1984 electorate — quite literally, it is a different set of people.
A healthy majority of voters this year were not eligible to vote in 1984; almost half of them weren’t even alive in 1972. People old enough to have cast ballots against McGovern will probably make up no more than 20 percent of the electorate in 2016. These are very old historical parallels.
Very old, and very lazy. As Daniel Denvir has written, the combination of factors that produced the McGovern disaster bears almost no resemblance to the political situation today. In 1972 the Democratic Party was in a state of flux. McGovern captured the nomination with about 25 percent of the primary vote; over 23 percent went to the Alabama white supremacist George Wallace. Major party leaders like AFL-CIO boss George Meany, meanwhile, refused to support McGovern in the general election against Nixon.
Today both major parties are far more ideologically unified and more polarized. Although the Democratic Party elite has so far shunned Sanders, he is almost as popular as Clinton among the party’s rank and file. If Sanders wins a clean majority of the primary vote, it’s hard to imagine any significant chunk of the Democratic coalition abandoning him in a general election against the Republicans.
But the historical analogies miss the mark for an even more fundamental reason. McGovern and Mondale did not lose because they were too liberal, but above all because they faced Richard Nixon and Ronald Reagan, popular incumbents presiding over economic booms.
The 1972 and 1984 blowout losses conform closely to electoral models that measure vote totals based on underlying economic conditions, without taking any account of candidate identity or ideology. The Democrats were doomed no matter who they nominated.
If the primary race continues to tighten, Clinton supporters will no doubt continue to spook Democrats with the fatal visions of 1972 and 1984. These are but McGoverns of the mind, false creations conjured by elite pundits and party officials. They offer no actual evidence that can be applied to the 2016 general election."