One year removed from Donald Trump's presidential election victory, many Democrats are still reeling from losing a contest they expected to win.

The loss still leaves many on the left bereft of ideas on how to move forward politically. Yes, there's been general agreement among Democrats in Congress to resist the Trump agenda at all costs. But that isn't necessarily a way to win the next presidential election. The resist-Obama Republicans of 2009-12 found that out the hard way in the 2012 election.

But there's one thing Democrats and liberals in general need to do fast if they want to move on from their 2016 election loss.

They need to get a divorce from Hillary Clinton.

In case anyone is unclear about how unwisely close and reverent too many liberals are to the very idea of their failed 2016 presidential nominee, this week's Vanity Fair comedy video debacle explains it all.

The magazine's website put out a short video with six suggested New Year's resolutions for Secretary Clinton. Some of the suggestions were kind, others not-so-kind. But the basic message was clear: Hillary, please don't run again in 2020!

In the context of the generally nasty political discourse these days, it was relatively inoffensive.

But Clinton's still very prominent supporters went crazy with anger. They attacked Vanity Fair and its editors with overwhelming outrage on social media for the better part of two days. The magazine was accused of sexism, racism, and hateful bias. Remember, this is the generally liberal Vanity Fair and not National Review we're talking about.

The heat got so bad by Wednesday that the magazine finally apologized. A Vanity Fair spokesperson said "It was an attempt at humor and we regret that it missed the mark." The video was not pulled off the internet, but as of Thursday morning it was no longer on the Vanity Fair website homepage, nor does it appear when you try an internal search on the site.

Even President Trump noticed how hard the magazine was trying to apologize to the liberal powers that be:

The point here isn't whether the video was funny or the jokes in poor taste. What's illuminating is that too many liberals and establishment Democrats are treating Clinton like she's still in the midst of the election. That's a dangerous problem for a party looking to move on and win.

By contrast, it seemed like the left was bemoaning and even making fun of Michael Dukakis and John Kerry mere seconds after their election losses in 1988 and 2004, respectively. In one example, then-Senator Joe Biden quickly led a movement after the 2004 election to criticize Kerry and his relatively weak response to the issue of terrorism. In the case of Dukakis, the usually liberal writers at Saturday Night Live didn't even wait for Election Day to begin depicting him as a hopeless loser.

Those quick turns away from losing choices played a big role in the Democrats' eventual comeback victories in 1992 and 2008. The 1992 Bill Clinton campaign made tireless efforts to divorce itself from the "old Democratic Party" of Jimmy Carter, Walter Mondale, and Dukakis. It wasn't just policy differences, but the stark image of a much younger candidate with a more persuasive personality that set him apart. The difference in energy levels between Dukakis and Bill Clinton alone were readily apparent.

Barack Obama's 2008 campaign would have stood in stark contrast to any Democrat before him because of Obama's historic role as the first African-American major party presidential nominee. But his campaign was a polar opposite of the Kerry strategy in many other ways as well. Most notably, it was again Obama's personality and speaking abilities that were put front and center, while Kerry's distant past as a Vietnam veteran was the hallmark of his campaign. It was a major persuasive upgrade.

It's important to note that in the aftermath of '88 and '04, the Democrats did not come up with their winning presidential candidates right away. The left has plenty of time to round up some better names in time for the 2020 primaries.

The issue here is that as long as Clinton remains as revered and protected in the public discourse as she is by leaders on the left, the longer it will take for them to truly grasp how weak and unpersuasive a candidate she was. The Democrats needs to close that persuasion gap and they can't do it if they can't see the gap in the first place. Cue up all the lessons and pithy sayings about how failure is the greatest educator and it's impossible to miss the point.

There's a similar diversion from the reality about Clinton in the obsession over allegations the Russians somehow fixed the 2016 election. But whatever special counsel Robert Mueller's collusion investigation finds, it's going to have to perform some miracles to prove a foreign power successfully tipped the scales for voters in all those Midwestern swing states that sent President Trump to the White House.

By all means, Mueller should continue his probe and prosecute any actual crimes. But as far as the 2016 results go, Occam's razor is the better explanation. The Democrats had a less persuasive candidate. She lost. Move on.

That seems like it was the short but priceless wisdom that short Vanity Fair comedy video was trying to pass on to its friends on the left. But all too many people on the left clearly rejected it, and the truth will remain elusive for them as a result. How do you make a brutal election loss worse? Refuse to stop making the same mistakes.

Commentary by Jake Novak, CNBC.com senior columnist. Follow him on Twitter @jakejakeny.

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