The incredible shrinking presidency of Donald Trump

(CNN)In the past 7 days, President Trump has attacked the following people -- and institutions -- on Twitter:

* LaVar Ball
* LiAngelo Ball
* Cody Riley
    * Jalen Hill
    * Marshawn Lynch
    * Jeff Flake
    * Hillary Clinton
    * Al Franken
    * The New York Times
    * CNN
    Three of those people are college freshmen at UCLA. One is a professional football player. Two are sitting senators. One is the woman he beat to win the White House almost a year ago. Two are major media organizations. And LaVar Ball is, well, LaVar Ball.
    And, this week is far from atypical for this president. As a candidate -- and now in the White House -- Trump has put his willingness to attack anyone at any time at the heart of his political persona. He is the guy who will never let you get a cheap shot in against him, the guy who will never let a punch thrown go unanswered.
    That sort of no-retreat, no-surrender mentality helped Trump the candidate immensely. Republican voters liked someone who was willing to speak his mind in the face of political correctness -- and someone who would never back down from a fight. Trump's if-you-come-at-me-I-will-destroy-you approach to, well, everything was appealing to a certain segment of GOP voters who thought that President Barack Obama spent the last eight years apologizing for America both in this country and around the world.
    As president, there was a belief in some circles that Trump might adjust his behavior -- act more "presidential." Hell, Trump himself promised as much!
    "I will be so presidential, you will be so bored," he said in mid-2016. "You'll say, 'Can't he have a little more energy?'"
    That has not been the case, however. And even Trump has abandoned the idea of being "presidential."
    "My use of social media is not Presidential - it's MODERN DAY PRESIDENTIAL," he tweeted in July. "Make America Great Again!"
    Trump never really defined what "modern day presidential" actually meant to him. But, through his actions over the first 10 months (or so) of his presidency he's made clear how he sees the job: To project confidence, strength and victory always and, if anyone ever questions him on any of those fronts, he attacks.
    It doesn't matter if the person doing the questioning is a former political opponent, a member of Trump's own party, a cable TV host or a teenage basketball player. Trump has one speed in all of his interactions: Aggressively leaning forward -- and ready to run you over, rhetorically speaking, if you get in his way.
    Neil Cavuto, a Fox News anchor, criticized that method of "using a bazooka to respond to a pea shooter" and added another message to Trump: "Last time I checked, you are the President of the United States. Why don't you act like it?"
    What Trump has overseen with his "modern day presidential" approach is a remarkable shrinking of the presidency. The men who have held the office before him -- Democrats and Republicans -- seemed to understand the value and importance of being president. They resisted their lower urges to respond to every critic or to correct every claim made against them because they believed it would be beneath the dignity of the office. They viewed the presidency as the ultimate high road; you were bound by the people who elected you -- and the people who had come before you in the job -- to act a certain way in the office.
    By going back and forth with LaVar Ball or Marshawn Lynch or any of the dozens of other people Trump has elevated by feuding with them over his first 10 months in office, Trump has shrunk the presidency by several degrees. Can you imagine Obama spending his time in Twitter fights with some random quasi-celebrity who said something bad about him? Or George W. Bush?
    Trump views the presidency less as a place where he elevates the dialogue in the country than one where he has primacy in any sort of fight he wants. He's acting exactly as he's acted his whole life -- thin-skinned, quick triggered etc. -- but now has the backing of the entire federal bureaucracy behind him. He is now the President Celebrity-in-Chief. Not just the Celebrity-in-Chief.
    Which is fine for Trump. The idea that a 71-year-old man would fundamentally change the behavior he exhibited over the first seven decades of his life was always a far-fetched one.
    But, Trump's influence on the presidency is harder to dismiss as just "Trump being Trump." The smallness of how Trump defines his role as the most powerful person in the country has real and lasting effects on how people perceive the president and the presidency. And none of those impacts are good ones.