(CNN) On Wednesday, Donald Trump wrote his name in the history books. Or, more accurately, tweeted it.

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Which is interesting -- for a few reasons.

First, well, context. Wednesday was the first day of opening arguments in the Senate's impeachment trial into Trump's conduct in Ukraine. It was also a travel day for Trump; he was in the air for much of the day -- on the way back from the World Economic Forum in Davos, Switzerland. (Trump landed back in Washington on Wednesday night.)

Second, content. What Trump's Twitter feed was filled with on Wednesday was a slew of quotes and videos from a variety of Republican elected officials and surrogates insisting that there was nothing impeachable in his conduct in regard to Ukraine and that the whole thing was motivated by Democrats' anger that they lost the 2016 election.

It provided, for the 71.5 million people who follow Trump on Twitter, their own alternative news universe -- one in which Trump is the greatest president since Lincoln, and Democrats (and the media) were simply out to get him because they hate his success.

It's also worth considering this: Like his falsehoods , Trump's tweeting habit has picked up considerably since he was sworn in as president in January 2017. In those early days, Trump tweeted, on average, nine times a day, according to this terrific New York Times analysis from 2019. But within two years -- so, by last year -- Trump was tweeting at triple that rate. And on Wednesday, Trump tweeted almost 14 times as much as he was tweeting in those first few months of his administration.

Who cares, you say! The tweets are meant to be a distraction! Don't fall for it.

The exact opposite is actually true. The tweets are an important story for a simple reason: They provide us almost unfettered access into what is on the President's mind at almost every minute. It is the raw feed from Trump, the uncut, unedited look at how the most powerful man in America thinks and what the cares about.

And Trump views Twitter with the same sort of import to his success in politics (and life).

"I love Twitter.... it's like owning your own newspaper--- without the losses," he tweeted way back in 2012.

"Without the tweets, I wouldn't be here . . . I have over 100 million followers between Facebook, Twitter [and] Instagram. Over 100 million. I don't have to go to the fake media."

What Trump is doing with his explosion of tweets and retweets on Wednesday isn't terribly complicated, then. He is seeking to make sure that his followers are getting a very simple message: This whole impeachment trial you are seeing on the news is total BS. There's no "there" there. Just a bunch of angry Democrats. No reason to pay attention!

The "why" of Trump's record-setting day on Twitter is more intriguing, and more telling. Yes, some of it is simply the result of being cooped up on a plane all day. (Most people would just watch four movies on a transatlantic flight; Trump tweets.) But it's also difficult to see the volume of Trump's tweets and retweets -- on the day that the House impeachment managers lay out the case against him -- and not conclude that he is worried.

Now, maybe he isn't worried about being removed from office. (There is little evidence that there are 67 senators willing to vote to do so.) But Trump's Twitter frenzy does suggest that he is concerned about the the narrative of the impeachment trial turning against him -- and what it might mean for his re-election chances.

To that end, Trump appears to have deputized himself as a one-man propaganda factory -- using Twitter to fight back against his many enemies on impeachment and to keep the support of his allies firm.

So, sort of like the rest of his presidency, then.