Photo: Drew Angerer/Getty Images

In January 2016, Donald Trump was unusually unpopular among Republican voters for a Republican presidential candidate. The mogul’s net approval among his adopted party’s faithful was 19 points lower than Marco Rubio’s, 20 points lower than Ben Carson’s, and 24 points lower than Ted Cruz’s. Polls also indicated that the mogul was by far the least electable GOP candidate in the primary race: Gallup put Trump’s net favorability among independent voters at -27, more than two times lower than the next most unpopular Republican.

As Trump wracked up early primary victories, Establishment Republicans issued increasingly frantic warnings about the insurgent’s ideological treachery and electoral inviability. In early March, the previous GOP standard-bearer gave a speech decrying Trump’s ruinous economic policies, misogyny, and inability to defeat Hillary Clinton. Trump’s primary rivals condemned him as a conman, and even tried to form an alliance explicitly aimed at keeping his delegate totals down. Meanwhile, mainstream pundits incessantly echoed the conventional wisdom that a Trump nomination would all but cede the White House to Hillary Clinton.

For a while there, all this appeared to put a ceiling on Trump’s support. At the beginning of April, the Republican front-runner had yet to win a majority of delegates in any state. On the fifth of that month, Ted Cruz beat Trump in Wisconsin by a 48 to 35 percent margin.

But then things changed. Cruz’s victory in the Badger State made the threat of a contested convention plausible and concrete to GOP voters. Trump began emphasizing the argument that winning a plurality of delegates (as opposed to a majority) should be sufficient for him to secure the nomination — and that any other outcome would be “crooked” or “rigged.” Suddenly, Trump’s support in both polls and primaries shot up to unprecedented heights. Neither Rubio’s withdrawal from the race nor some regional change in the primary calendar could fully explain this shift. As Nate Silver wrote at the time:

What happened after Wisconsin? My theory as of a couple weeks ago — and having not gotten so many other things about the Republican race right, I’m sticking to it — is that Republican voters were swayed by Trump’s arguments that the candidate with the most votes and delegates should be the nominee. (Meanwhile, voters regarded Cruz’s wins over Trump at state party conventions as undemocratic.) Some voters might have preferred Cruz or John Kasich to Trump in the abstract, but not at the expense of a contested convention in which the plurality winner would be denied the nomination and replaced with another flawed candidate.

Photo: The Green Papers via fivethirtyeight

Which is to say: Once the threat of a contested convention became tangible, Trump-skeptical Republicans opted to unify behind a nominee they didn’t love — and whom they’d been given every reason to consider unelectable and unacceptable by party elites and Establishment media — out of an ostensible aversion to prolonging intraparty discord and embracing an anti-democratic process.

Democratic elites would be wise to mind this recent history.

Or, more precisely, the segment of such elites who disdain Bernie Sanders would have been wise to remember to do so before telling the paper of record that they’re preparing to block the socialist senator’s nomination by any means necessary.

As the New York Times reports:

Dozens of interviews with Democratic establishment leaders this week show that they are not just worried about Mr. Sanders’s candidacy, but are also willing to risk intraparty damage to stop his nomination at the national convention in July if they get the chance. Since Mr. Sanders’s victory in Nevada’s caucuses on Saturday, The Times has interviewed 93 party officials — all of them superdelegates, who could have a say on the nominee at the convention — and found overwhelming opposition to handing the Vermont senator the nomination if he arrived with the most delegates but fell short of a majority …

Jay Jacobs, the New York State Democratic Party chairman and a superdelegate, echoing many others interviewed, said that superdelegates should choose a nominee they believed had the best chance of defeating Mr. Trump if no candidate wins a majority of delegates during the primaries.

There are obviously important differences between the voting behavior of each party’s base (Democratic voters have historically been less ideological and antagonistic to their party’s leadership than GOP ones). But there’s little reason to believe that Democratic voters wouldn’t emulate their Republican counterparts, were they presented with a choice between rallying behind their party’s insurgent front-runner, or accepting the inevitability of a contested convention.

After all, most of the distinctions between the two contexts make the prospect of unifying behind Bernie Sanders more appealing for Democrats than unifying behind Trump was for Republicans.

In January 2016, Trump had an exceptionally low in-party approval rating; in January 2020, Sanders had an exceptionally high one.

BREAKING: @BernieSanders has the HIGHEST favorable approval rating of ANYBODY running for President.



76%. Highest in years.



That's a whole lot of NOBODIES.



Now, don't just be a fan -donate, organize, volunteer.



Join millions of nobodies @ https://t.co/G73asEw31q#iLikeBernie pic.twitter.com/5gv2gTlAQ6 — Shaun King (@shaunking) January 21, 2020

In fact, multiple recent polls have shown the Vermont senator boasting better favorability numbers among Democratic voters than any other 2020 candidate. Meanwhile, a Yahoo News/YouGov survey released earlier this month found Sanders beating every one of his Democratic rivals in a two-way contest.

#National Democratic Primary, Head-2-Head:

Sanders 54% (+21)

Klobuchar 33%

.

Sanders 54% (+17)

Buttigieg 37%

.

Sanders 53% (+15)

Bloomberg 38

.

Sanders 48% (+4)

Biden 44%

.

Sanders 44% (+2)

Warren 42%@YouGovUS/@YahooNews 2/12-13 pic.twitter.com/PmqYFO2f7B — Political Polls (@Politics_Polls) February 14, 2020

After triumphing in early states, Sanders has weathered some attacks from his primary rivals. But none have been nearly as brutal as those that Trump endured. Marco Rubio never insisted that he liked Trump personally before assailing his fitness for the nomination; Amy Klobuchar and Joe Biden routinely stipulate their personal affection for their longtime colleague before critiquing his policies. What’s more, the broader Democratic Establishment isn’t nearly as united in opposition to Sanders as the GOP’s was to Trump. Several Senate Democrats told Politico last week that they are confident Sanders can beat Donald Trump. And Nancy Pelosi told her caucus Wednesday that she expects them to “wholeheartedly embrace” the party’s standard-bearer, “no matter who the nominee is for president.”

While the mainstream press has presented Democratic voters with no small number of warnings about the 78-year-old socialist’s general election liabilities, these arguments aren’t nearly as well substantiated as indictments of Trump’s electability were circa February 2016. At this time four years ago, Trump’s net-approval among the general public was -23 percent. Today, Sanders’s net-approval is -2.7. Joe Biden’s, by contrast, is -5.4; Michael Bloomberg’s is -7; and Elizabeth Warren’s is -7.3. Further, hypothetical general elections polls show the Vermont senator performing about as well, if not better, than his rivals against Trump: On Thursday morning, Muhlenberg College (an A+ pollster, per 538) released a poll of Pennsylvania in which Sanders is the only Democrat who bests the incumbent president.

PENNSYLVANIA

Sanders 49% (+3)

Trump 46%

.

Trump 47%

Biden 47%

.

Trump 47%

Warren 47%

.

Trump 45% (+1)

Klobuchar 44%

.

Trump 46% (+1)

Buttigieg 45%

.

Trump 48% (+3)

Bloomberg 45%@mcall/@Muhlenberg 2/12-20 — Political Polls (@Politics_Polls) February 27, 2020

Anti-Sanders Democrats do have a path for blocking his nomination. The last batch of South Carolina polls suggests Joe Biden may pull out a landslide victory Saturday. If so, the former vice-president may be in a position to limit Sanders’s delegate haul on Super Tuesday, and then power past him (perhaps, with the aid of an infusion of Bloomberg bucks) over the ensuing months. Which is to say: If the moderate wing of the party can coordinate well enough to present Democratic voters with a clear choice between Sanders and Biden, they might (emphasis on might) be able to keep blue America from “going red.”

But if the only choice they can offer is one between Bernie Sanders and a contested convention, there is every reason to believe Democratic voters will unite behind their socialist standard-bearer before delegates descend on Milwaukee.