The ghost of George McGovern walks the Earth — or, at least, haunts the pages of center-left and center-right columnists. As Bernie Sanders' campaign continues its winning streak, and begins to attract bandwagoning support from undecided voters looking for a winner, it's not just Michael Bloomberg wondering whether the Democrats aren't repeating their worst electoral decision in modern times, and giving President Trump's re-election campaign exactly what it wants.

But the McGovern analogy has a great many problems. For one thing, McGovern wasn't an across-the-board revolutionary; he was a moralist whose rise was powered by a specific issue: forthright opposition to the Vietnam War. Far from presenting himself as the champion of the party's traditional labor base, that base was the biggest reason why McGovern lost in the general election, as the AFL-CIO failed to endorse for the first time since its founding.

McGovern also won not by attracting a clear plurality of support that snowballed into a majority, but by cannily exploiting the new nomination system put in place after 1968. Finally, it's important to recall that McGovern was crushed by Richard Nixon, whose approval ratings had barely dipped below 50 percent during his first term, and who combined partisan rhetorical pugnacity with a genuinely moderate stance in government. In many ways, Jimmy Carter in 1976 and Howard Dean in 2004 are better analogies for McGovern's 1972 campaign than Bernie Sanders' crusade, at least in its 2020 incarnation.

In fact, assuming Sanders wins the nomination, it'll be the first time the modern Democratic Party has never experienced a phenomenon quite like it: a candidate of an ideological faction running explicitly against the party leadership to take the party over and restore it to its purported true soul, and winning. But the Republican Party has experienced something similar — three times, in fact: In 1964, 1980, and 2016.

Perhaps those precedents tell us more about what Sanders could portend.

Goldwater: the Harbinger

Like father of the conservative movement Barry Goldwater, Sanders is a factional candidate of the true faith, the representative of those who believe his party has lost touch with its ideological moorings. His brand is consistency and sincerity, which wins him affection if not support even from some opponents. But those very same qualities make it easy for the opposition (both within and outside the party) to tar him as a radical and an extremist.

Sen. Goldwater lost the 1964 presidential election badly — but he was running against Lyndon Johnson, a legislative titan whose approval rating was over 75 percent that February. And Goldwater transformed his party nonetheless. His opposition to the 1964 Civil Rights Act began the process of ideological realignment that turned the South solidly Republican, a key factor powering Ronald Reagan's victorious quest for the presidency in 1980 and Newt Gingrich's capture of the House of Representatives in 1994.

How did Goldwater's thrashing ultimately lead to a Republican majority? The answer is both ideological and demographic. Goldwater realigned the Republican center toward the South and West, the fastest-growing regions of the country. Increasing dominance in these regions led to a substantial electoral college advantage that wasn't broken until 1992. Ideologically, meanwhile, he gave Republicans something to be for rather than merely against. That's why they were able to define a new political era when Reagan won.

That's the promise that Sanders holds even if he loses: that he opens the door not only to a return to power, but a transformation of the terms of the debate, something neither Clinton nor Obama — nor Eisenhower, Nixon, or Bush — achieved, but that FDR, Johnson, and Reagan did. But what's the demographic basis of Sanders' rise? And could it actually point to a dominant coalition, whether it manifests in 2020 or a subsequent election?

The elections of 2016 and 2018 pointed to a new alignment in which Democrats dominate in cities — including in most red states — while Republicans dominate in rural areas — including in most blue states. That leaves the relatively comfortable and well-educated suburbs as the primary battleground between the parties. It's a map that makes it quite a bit easier for Republicans to win the White House, and much easier for them to hold the Senate — which is one reason for Democrats to actively seek some other alignment. But does another alignment exist?

If it does, it might look like the one Sanders' coalition points to, powered by demographic change in the fastest-growing states — particularly Texas, the keystone of the Republican electoral coalition. As Sanders' Nevada victory showed, his best demographic groups are young voters and Hispanic voters. He does well with less-educated voters, a group Warren and Buttigieg have struggled with, but they aren't the same downscale voters Trump (or Biden) appeal to. They're younger and browner, and they're located in the same states that once powered Goldwater's coalition.

Sanders' ability to blunt Trump's appeal to rural whites, the bedrock of his coalition that enabled him to win the Electoral College in 2016 and hold the Senate in 2018, probably isn't as good as Biden's. His ability to energize well-educated suburban white women, who powered Democrats's 2018 resurgence in the House, remains to be demonstrated; it probably trails that of Elizabeth Warren. Those are reasons to worry about Sanders' general election prospects, even though Trump is no Johnson.

But the Sanders coalition is in a very real sense the future of the Democratic Party, and that's a reason to take notice of his primarily class-based politics, because they have shown far better ability to energize the demographic future than any of his opponents.

Reagan: the Transformer

Could Sanders be more than a harbinger, though, and achieve something like Ronald Reagan's breakthrough? There are tempting parallels.

Reagan challenged the incumbent Gerald Ford for the nomination in 1976 and nearly took the nomination from him, much as Sanders gave Hillary Clinton a far tougher run for her money than anyone could have imagined. And like Reagan, Sanders has demonstrated the ability to be far more pragmatic in government than he is often given credit for, working within the system and demonstrating an admirable institutional conservatism with his support for the filibuster and opposition to court packing. His historic support for gun rights even has a parallel in Reagan's support for abortion rights as California governor.

Moreover, Trump bears some comparisons to Jimmy Carter. His personal popularity is poor, and he has proven largely unable to transform his party in policy terms. Moreover, like Carter he leads what is arguably a demographically declining coalition of older voters in shrinking states. And if you think Trump is a failed "disjunctive president" at a moment when the winds of populism are blowing, then Sanders is the obvious successor. He would be able to steal Trump's populist thunder, waving the White House's Medicare-cutting budget like a bloody shirt, much as Reagan was able to accelerate Carter's deregulatory reformism and military buildup.

But Trump-Carter comparisons are limited by two facts. First, Carter not only was unable to transform his party ideologically (as Trump largely has); he was also unable to establish control of it institutionally. That is emphatically not the case with Trump, who continues to purge his administration of disloyal elements and has struck fear in the heart of nearly every Republican senator not named Mitt Romney. Trump has faced primary challengers in 2020, but nothing remotely on the scale of Ted Kennedy's challenge to Carter. The Republican Party in 2020 will be absolutely unified behind Trump.

That's why, if there is a John Anderson figure in 2020 — someone who gives voters permission to vote against someone they are determined to oppose without voting for someone they are determined not to support — Sanders faces at least as much risk of defections from his coalition as Trump does. Although he was a Republican, Anderson pulled most of his votes from Carter's column rather than Reagan's. Similarly, if Michael Bloomberg or someone like him decides to run as an independent, his support will likely be concentrated among voters who were never part of Trump's coalition, but who cannot stomach Sanders.

The other enormous difference is the economic background to the election. While Trump suffers from Carter's approval ratings, he has Johnson's economy to run on. Unless that changes, the prospects of Sanders leading a decisive electoral repudiation of Trump seem quite limited indeed.

Trump: the Conqueror

That leaves one further comparison: Trump himself. It's worth stressing that, unlike Trump, both Goldwater and Reagan were loyal Republicans. Reagan even proclaimed that the 11th Commandment was, "Thou Shalt Not Speak Ill of a Fellow Republican." There is, needless to say, no equivalent verse in Sanders' scripture.

Like Trump, Sanders comes from outside the institutional party he seeks to lead, and a substantial portion of his appeal rests precisely on that independence, and on pent up frustration with the party leadership. Like Trump, Sanders is leading a movement deeply bound up with his own persona, something hard to imagine sustaining itself in his absence. And like Trump, were Sanders to achieve victory, he could face persistent resistance within the party to promoting his agenda, and he would certainly have difficulty staffing his administration with people associated with his movement rather than the institutional party. That's a fact that will surely affect the actual course of policymaking in a Sanders administration as it has in Trump's.

But there are two crucial differences between Sanders and Trump. First, Sanders is a sincere ideologue like Goldwater and Reagan, not an opportunist. He is running to transform his party ideologically rather than simply conquer it and make it his plaything. There's a reason why Trump has done so little to actually turn the GOP into a worker's party and to repudiate the wealth-favoring policies backed by its donors: Because he is not actually that interested in policy. Sanders is.

That difference cuts both ways, however. It makes it easier for Sanders to get between Trump and his lies, and separate him from that portion of his supporters who believed he was a relative moderate in 2016. But it also makes it easier for Trump to retain the loyalty of his party's regulars, and to separate Sanders from the portion of his coalition that is worried about him not because he might lose but because he might win. Cynicism has its advantages as well as its drawbacks.

But another difference is even more important. Trump took over a party that absolutely despised its leadership. As I have noted multiple times before, there was no anti-Trump majority within the GOP in 2016 to be consolidated; there was an anti-establishment majority divided between Trump and Cruz, which Trump ultimately consolidated. Trump was able to decapitate the GOP because the head was already completely dislocated from the body.

The Democrats' complaints about their leadership are quite different. While Sanders' core voters are enraged by what they see as a smug, corrupt and out-of-touch nexus of donors and consultants at the heart of the Democratic establishment, the party faithful as a whole are not in a state of mass revolt. The presence of Joe Biden at the top of the polls for most of the campaign reflects a party pretty happy with what it stands for, and concerned primarily with how to beat Trump — and concerned about their leadership primarily because they aren't sure they have what it takes to beat him.

This has real bearing on a question that has kept the Democratic leadership up at nights: whether they can afford to attack Sanders directly for his views, or whether that risks alienating "Bernie or bust" voters who they will need in November. The answer, I believe, quite clearly is yes, because these voters do not define the base of the party, and a party must be defined by its broad base, not by an angry rejectionist minority faction.

While he comes from outside the party, Sanders isn't an alien implant like Trump. If he wins, it'll be because regular Democrats decide he looks like a winner. To beat him, someone else has to quickly demonstrate that he isn't. Denying Sanders the nomination through backroom chicanery would split the party in two.

But a genuine ideological fight is something the party not only can afford but must have, and will be stronger for — as the GOP was — regardless of which side wins.

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