(CNN) Just after 10 a.m. ET Monday, Donald Trump typed out his first tweet of the day: "Most politicians would have gone to a meeting like the one Don jr attended in order to get info on an opponent. That's politics!"

A few things:

1. It's not politics. And by "it" I mean the eldest son of the Republican presidential nominee meeting with a Russian lawyer with the promise of incriminating information about a political opponent.

2. This is today's example of how Trump sees himself as fundamentally altering the way in which the presidency can and should work. President Barack Obama tweeted very occasionally and almost always about policy matters. President Trump tweets constantly about all sorts of things; his Twitter feed is a direct line into his way of thinking at any given moment.

And Trump believes that's a very good thing. He has repeatedly insisted the media wants him to stop tweeting because they don't like how it allows him to communicate directly with his supporters. (To be clear: The last thing the media wants is for Trump to stop tweeting.)

To those who argue Trump should tweet less -- a group that includes virtually every elected Republican official -- Trump offered this response, via Twitter of course, last month: "My use of social media is not Presidential - it's MODERN DAY PRESIDENTIAL. Make America Great Again!"

What's clear in new polling data from the Washington Post and ABC News: People don't like "modern day presidential." Not at all.

Seven in 10 people in the poll say that Trump's "behavior as president" is "unpresidential" as compared to 24% who describe it as "fitting and proper." Those numbers are eye-opening -- particularly given that almost 4 in 10 Republicans (38%) say that Trump has acted unpresidential since entering the office. And, as ABC's polling analyst Gary Langer notes, 48 percent of evangelical white Protestants and 55 percent of non-college-educated white men -- two groups that strongly supported Trump in 2016 -- also say his behavior is something short of presidential.

Trump's Twitter addiction plays a central role in the views of him as less than presidential. More than two-thirds in the Post-ABC poll say that Trump's tweets are "inappropriate" (68%) or "insulting (65%). A majority (52%) say the tweets are "dangerous." Just 1 in 5 (21%) call the tweets "refreshing; that includes just 41% of self-identified Republicans who describe the tweets as "refreshing."

All of those numbers make a very simple point: For all of Trump's scapegoating of the mainstream media, he has only one person to blame for his current dismal poll standing: himself.

Trump is his own worst political enemy. He repeatedly ignores the advice of lawyers, advisers and even family members when it comes to how he needs to act, talk and tweet. He refuses to change or, short of that, even adjust.

In Trump's mind, that he won the 2016 election when almost everyone said he wouldn't is all the validation he needs -- or will ever need -- to do whatever he wants, no matter what people say about it. Polls? Polls were wrong about him winning so why wouldn't they be wrong again? (Sidebar: Polls weren't really all that far off.)

There is, of course, a chance that Trump is, again, right -- that no matter what the polls show, his redefining of what "presidential" means and looks like as well as his constant tweeting endear him as an outsider to voters.

But all available data suggests the exact opposite. The polling makes very clear that people don't like Trump's "modern day presidential" mien -- and like his Twitter feed even less.

Of course, if you think Trump will change, then you haven't been paying attention these past six months.