On the day President Donald Trump's impeachment trial commenced, Hillary Clinton put the spotlight on her 2016 Democratic primary battle with Sen. Bernie Sanders.

Clinton said she wouldn't commit to supporting Sanders if he won the Democratic nomination.

But Sanders didn't behave much differently than any other primary opponent in 2016 and campaigned vigorously on her behalf after she clinched the nomination.

The Clinton campaign's hubristic strategy of taking for granted the Midwestern "blue-wall" states of Michigan and Wisconsin (both of which Clinton lost to Sanders) likely had a lot more to do with her defeat.

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Hillary Clinton has taken another swing at her 2016 Democratic primary rival Sen. Bernie Sanders.

In an interview with The Hollywood Reporter released on Tuesday, the former secretary of state wouldn't commit to supporting Sanders if he won the 2020 Democratic nomination, citing "his online Bernie Bros and their relentless attacks on lots of his competitors, particularly the women," which she said were tacitly supported by his campaign leadership and perhaps Sanders himself.

Sanders responded in a statement: "My focus today is on a monumental moment in American history: the impeachment trial of Donald Trump. Together, we are going to go forward and defeat the most dangerous president in American history."

Clinton's underlying beef with how Sanders affected her failed run in 2016 is ahistorical. Some of her grievances were, in fact, fairly standard behavior by a primary opponent, and her accusation that Sanders only half-heartedly supported her candidacy against Trump is belied by the evidence.

So why, on the first day of Trump's impeachment trial, would Clinton grab the spotlight and place it on a years-in-the-past intraparty squabble?

'Nobody likes him'

Clinton was quoted as saying in the upcoming Hulu docuseries "Hillary" that the democratic socialist senator from Vermont is a "career politician" who got "nothing done" in Congress. Clinton added, "Nobody likes him; nobody wants to work with him," seemingly referring to Sanders' colleagues in the Senate (of which Clinton was one for eight years).

There's likely some truth to that. Sanders isn't even a Democrat (he's an independent), and his staunch opposition to mainstream Democrats' economic positions and capitalism alike have made him a nuisance to the party he has caucused with on more than one occasion.

Shortly after Sanders entered Congress in 1991 as a freshman representative in Vermont, the longtime liberal Massachusetts congressman Barney Frank said "Bernie alienates his natural allies" and that his "his holier-than-thou attitude — saying in a very loud voice he is smarter than everyone else and purer than everyone else — really undercuts his effectiveness."

Frank later conceded that Sanders eventually learned to play nice with his congressional colleagues but that after a quarter century in office, he had "little to show for it in terms of his accomplishments, and that's because of the role he stakes out."

But Clinton's most recent comments reveal that her problem with Sanders isn't merely that he was an annoying member of the left flank. It's that she believes he didn't sincerely and effectively campaign for her in 2016 after she locked up the Democratic nomination after a bruising primary fight that laid bare Clinton's vulnerabilities as a candidate.

A tale of 2 vanquished candidates

In an interview with Howard Stern in December, Clinton repeated her belief that Sanders' delay in endorsing her candidacy caused substantial damage to her general-election campaign.

It's true that after the last primaries in early June, Sanders waited a full month to endorse Clinton. By contrast, it took Clinton less than a week after the last primaries to endorse Barack Obama in 2008.

But Sanders was a relentless campaigner for Clinton in the last two months of the 2016 campaign, appearing at 39 rallies in 13 states on behalf of the nominee, at times facing sustained boos from his supporters for throwing his support behind Clinton.

Looking at data and historical precedent around the 2016 election, there's little indication that Sanders played any more of a spoiler role than a typical primary challenger.

For one thing, there was already a significant section of the party who preferred someone over Clinton. In April 2015, 38% of respondents in Gallup poll who identified as Democrats said they did not want Clinton to be the nominee. The point being, if it weren't Sanders representing the anti-Clinton liberals, it would have likely been someone else.

But Clinton is still irritated that Sanders called her "unqualified" to be president and blames the candidate for giving voice to what was a large anti-Clinton sentiment among Democrats.

Primary battles are civil wars, and Clinton's campaign threw some artillery at Obama during the 2008 contest.

Clinton's chief strategist, Mark Penn, sent a memo to the candidate that recommended framing Obama as "not at his center fundamentally American in his thinking and in his values" as a campaign strategy. And in May 2008 — a month after she had been mathematically denied a majority of delegates — Clinton cited the June 1968 assassination of Sen. Robert F. Kennedy as a reason to stick it out until the bitter end.

Sanders, like Clinton, stayed in the race until the last primary votes were cast.

Following the defeat of a primary rival, it's not atypical for fans to remain attached to their first choice. Before there were Bernie Bros, there were "PUMAs" — an acronym for the pro-Clinton political action committee "People United Means Action" that its members unofficially dubbed "Party Unity My Ass" — who were not easily convinced that they should forgive and forget the nasty primary fight and line up behind Obama.

And even after all of this, most Sanders supporters stuck with Clinton in the general election.

That year, a YouGov survey showed 24% of respondents who identified as Clinton primary supporters ended up voting for Republican nominee John McCain that November. In 2016, the highest estimates showed 12% of Sanders primary supporters voting for Trump.

Bernie's not the reason Hillary lost

Die-hard Clinton supporters, and the former secretary of state herself, maintain that the "toxic" air surrounding Sanders' campaign was a major factor in her 2016 defeat to Trump.

A not insignificant number of "Bernie Bros" can be obnoxious sexist bullies online, but they are not representative of the majority of his supporters.

But Robert Wheel wrote in a thorough data-driven study for the University of Virginia's Center for Politics that the reason the toxic Bernie Bro online phenomenon was "so prominent is that men in their 20s spend the most time online and, I speak as a former man in his 20s, are the most strident people online." He implored Clinton diehards to understand "the election was not your Twitter mentions."

Wheel also brought up elements such as the relentless coverage of Clinton's email servers, the infamous letter by then-FBI Director James Comey to Congress a week before the election, the Russian social-media disinformation campaign, and the Clinton campaign's hubristic strategy of taking for granted the Midwestern "blue-wall" states of Michigan and Wisconsin (both of which Clinton lost to Sanders).

It's also worth noting that Clinton was second only to Donald Trump in 2016 as the least popular major party candidate since such metrics were measured. Even after losing what should have been an unlosable election to a reviled reality-TV game-show host, Clinton's favorability ratings continued to drop, eventually falling to below Trump's.

Clinton is entitled to hold a grudge against Sanders and his supporters if she chooses. But to assert that his primary attacks were so beyond the pale that they kept her from winning the presidency, or that the dozens of rallies at which he appeared on her behalf were empty gestures, feels more like echo-chamber thinking than a historically accurate reading of how 2016 went down.