When Jerry Seinfeld decided to call it quits on his hit show Seinfeld after nine seasons, the show was sitting on top of the Neilsen ratings, the critics loved it, and the network was offering eye-popping dollar amounts to renew for another year.

And to the surprise of many, Seinfeld said, “Thanks, but no thanks.”

When Howard Stern asked Seinfeld to explain why he didn’t continue the series, he said, “The public wanted more. But, Howard, the public is not in show business. So you should do the opposite of what the public wants. There’s a reason they are not in show business.”

In short, Seinfeld believed that the act had played itself out and he wanted to go out as king of the hill.

And that’s what makes Jerry Seinfeld different from virtually everyone else in public life; most people don’t exit the stage as gracefully. They’re more likely to be hanging onto the curtains as they’re dragged out by a guy with a walkie-talkie.

Which brings us to former New York senator and 2016 Democratic nominee for president, Hillary Clinton.

After two failed bids for the presidency, if you thought that Clinton would quietly ride off into the sunset, you would be mistaken.

Since her November loss to New York billionaire Donald Trump, Hillary Clinton’s whole presentation has been the proverbial Academy Awards speech that has gone on way too long, with the orchestra at the Democratic National Committee playing louder and louder as she keeps talking.

First, Clinton gave an interview to CNN’s Christiane Amanpour blaming her election loss on then-FBI Director James Comey, sexism and Russian interference.

Clinton told Amanpour, “I’ve been in a lot of campaigns and I’m very proud of the campaign I ran. … It wasn’t a perfect campaign — there’s no such thing — but I was on the way to winning until a few things happened. … If the election was on Oct. 27, I’d be your president.”

Then, Clinton delivered the commencement address at her alma mater, Wellesley College, and aggressively went after President Trump, even implicitly comparing him to former President Richard Nixon.

But while I’m sure it’s cathartic for Clinton’s super fans to have her remain on the scene as Trump’s chief antagonist, it’s downright suicidal for the Democratic Party.

When the Clintons stay in the spotlight, instead of moving on gracefully, like Jerry Seinfeld, they suck up all the oxygen that could be going to Democrats who are on the ballot in the 2018 midterm elections or who are trying to establish a national profile so they can run for president in 2020.

If the country remains locked in a Trump/Clinton binary world the Democrats won’t have an opportunity to move on to act two, and there’s no question that this scenario benefits the Republican incumbent.

According to a Washington Post poll conducted last month, when survey respondents were asked how they would vote if the election were held today, 43 percent say they would support Trump and 40 percent say Clinton — a five point swing in Trump’s direction since election day.

Former Vice President Joe Biden recently echoed the sentiments of this poll while speaking at a conference in Las Vegas. “I never thought she was a great candidate. I thought I was a great candidate,” he concluded.

But he didn’t run and she did. And yada, yada, yada the Democrats got wiped out … and the reruns live on every day on cable news.

John Phillips is a CNN political commentator and can be heard weekdays at 3 p.m. on “The Drive Home with Jillian Barberie and John Phillips” on KABC/AM 790.