What happens when Democrats lose an election they were sure they were going to win? Time to rearrange the entirety of the American electoral system! Democrats are seeking to expand voting rights to, well, just about everyone — until they get their desired result.

The new hotness is lowering the voting age to 16 years old — as proposed in the House bill HR 1, the For the People Act of 2019.

I’ve written in these pages about the arbitrary points of adulthood in America: 18 to join the military, 21 to drink, but if you get accused of a crime, you can be tried as an adult at 13. We shouldn’t add another layer of arbitrariness by giving 16-year-olds the right to vote.

Asked about the proposal in March, House Speaker Nancy Pelosi said it’s “important to capture people when they’re in high school.” Telling language. But high schoolers don’t tend to be the most civic-minded people. Nor do they want to be “captured.”

The Grabien news site compiled tweets from people responding to Pelosi’s statement by recounting the insane things they did when they were 16. One example: “When I was 16, I sucked a drinking glass to my face for 10 minutes and gave my lower face a giant hickey that took 3 weeks to heal.”

“Voting is a responsibility,” we tell our children. Gather information, make the best decision. “Cool,” the American teen replies, “right after I inhale this Tide Pod.”

Eighteen is the right line of ­demarcation for adulthood. It’s the age most people finish high school and start making plans to live on their own. It’s the time we can start trusting most kids to lay off the Tide (that’s a sad commentary on American modernity, but we are where we are).

In March, Rep. Ayanna Pressley (D-Mass.) argued for the change, saying: “Those who have a stake in our democracy will also have a say in our democracy.”

But that’s pretty much everybody, everywhere. And that’s why the argument isn’t stopping with just 16-year-olds.

Letting inmates vote while still in prison is another Democratic brainstorm. I agree that ex-prisoners, who have served their time, should have their rights restored. But those who have been removed from society and stripped of their most basic citizenship rights? No, they shouldn’t still have the ability to choose the nation’s leaders.

“But why stop at citizens anyway?” asks the Left. A 2018 opinion piece by Gustavo Arellano in the Los Angeles Times was headlined: “Let noncitizens vote. What’s the worst that could happen?”

Wrote Arellano: “Conservatives need to calm down. Noncitizen voting already is happening in some Maryland towns, and democracy there is still alive. Giving them access to the ballot box is a great gesture — it lets more people hold government accountable, adds a shot of vitality to our democracy, blah, blah, blah.”

Yep, that “blah, blah, blah” line appeared in a major newspaper.

But yada, yada, yada, why even limit it to noncitizens living in America? We can open our ballot boxes to citizens of the world! If we did, Russian interference in the 2016 election wouldn’t even be that big of a deal.

In March, French writer Clé­mence Michallon, writing in The Independent, made just this call. US policy affects people in other countries, she argued, so why shouldn’t they get to shape American democratic outcomes?

The Left lost its collective mind over the election of President Trump. Voters must decisively reject liberals’ attempts to subvert our system, born of their election trauma.

No, we shouldn’t let 16-year-olds or prisoners or non-citizens vote. The rules shouldn’t be changed just because the Democrats lost.

One responsibility that comes with living under a democratic system is having to accept that sometimes you lose.

Scrapping the longest-running democratic experiment in history over one loss is a step too far. If you want to help 16-year-olds be part of the process, start by showing them how to handle electoral loss.

Twitter: @Karol