(CNN) Even as the 2020 race begins in earnest, President Donald Trump is already suggesting that Democrats cannot beat him fairly -- raising the specter that if he loses next November, he will suggest that the election was not legitimate.

"The Democrats in Congress yesterday were vicious and totally showed their cards for everyone to see," Trump tweeted Tuesday, referring to House Democrats' launching of a broad-scale investigation into him. "When the Republicans had the Majority they never acted with such hatred and scorn! The Dems are trying to win an election in 2020 that they know they cannot legitimately win!"

Trump 2020 campaign press secretary Kayleigh McEnany echoed that sentiment in a statement on the Democratic investigations. "These desperate Democrats know they cannot beat President Trump in 2020, so instead they have embarked on a disgraceful witch hunt with one singular aim: topple the will of the American people and seize the power that they have zero chance at winning legitimately," she said.

And asked Wednesday about the Democratic investigations, White House press secretary Sarah Sanders said this: "They continue to be a group totally taken by small radical leftist fringe of their party and they're completely controlled by it, they know that's not enough to beat this President so they're going to look for other ways to do that."

All of that rhetoric fits into a very clear pattern: Convince the Trump base that it is not possible for him to lose a fair and legitimate election in 2020. Thus, if he loses, it must be, by definition, illegitimate.

None of this should be surprising, given Trump's oft-stated view of the 2016 election -- in which he won the Electoral College but lost the popular vote to Hillary Clinton by nearly 3 million votes.

Less than three weeks after winning the White House in 2016, Trump sent out this tweet: "In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally."

In a meeting with a bipartisan group of lawmakers just days after his inauguration, Trump was at it again -- reportedly telling the gathering that somewhere between 3 and 5 million illegal votes were cast in the 2016 election and, had only legitimate votes been cast, he would have won the popular vote in addition to the Electoral College.

Neither Trump nor anyone in his administration has ever provided any evidence of his claims of widespread illegality. A commission formed by Trump -- and chaired by failed Kansas gubernatorial candidate Kris Kobach -- was disbanded after less than a year. And study after study has shown that widespread voter fraud -- of the sort alleged by Trump -- simply does not exist.

Of course, Trump is less interested in the facts about voter fraud -- or lack thereof -- than he is about convincing his base that if he loses, it's not because he got less votes, it's because something nefarious is being perpetrated against him by the elites.

How do I know? Because Trump was doing it in the 2016 election -- before he knew he actually won.

In an interview on Fox News Channel on Election Day 2016, Trump said this:

"It's largely a rigged system. And you see it at the polling booths, too. There are reports that when people vote for Republicans the entire ticket switches over to Democrats. You've seen that. It's happening at various places today. It's been reported. In other words, the machines, you put down a Republican and it registers as a Democrat. They've had a lot of complaints about that today."

So, yeah.

This is straight from the Trump blueprint -- and not just in politics, either. In his past life as a businessman, Trump would regularly declare victory on a deal loudly and publicly -- even when the facts didn't bear out his bluster. Hell, he somehow spun three bankruptcies as wins for him!

It's not just that Trump doesn't like losing. (No one likes losing.) It's that he is unwilling to accept any sort of loss for fear that defeat might take some of the shine off of his all-I-do-is-win persona.

In the business world, that approach was mostly harmless. Trump could say whatever he wanted but, at the end of the day, it was pretty clear who won and who lost a deal. Money, usually, changed hands. And while lots of people Trump dealt with rolled their eyes about his massive exaggerations, they usually just ignored them.

In politics, Trump's inability to accept that he could lose fair and square is far, far more dangerous.

Michael Cohen, Trump's former longtime fixer, said as much during his congressional testimony in front of the House Oversight Committee last month. "Given my experience working for Mr. Trump, I fear that if he loses the election in 2020, that there will never be a peaceful transition of power," said Cohen.

Sit with that for a minute. And realize what it would mean if the sitting incumbent President of the United States simply refuses to concede he has lost in 2020.