Story highlights Michael D'Antonio: Vice President Biden said that Trump should grow up and adjust to his new role

Trump has adjusted his persona when needed but he's never faced anything like this, writes D'Antonio

Michael D'Antonio, the author of "The Truth About Trump," is writing Trump Watch, a series of columns on President-elect Donald Trump for CNN Opinion. The opinions expressed in this commentary are his.

(CNN) Vice President Joe Biden had some sharp words of wisdom for the incoming President-elect last week.

"Grow up, Donald. Grow up. Time to be an adult," he said in an interview on PBS. "You're president. You've got to do something. Show us what you have. You're going to propose legislation. We're going to get to debate it. Let the public decide. Let them vote in Congress. Let's see what happens."

Biden's remarks came during a continuing stream of inflammatory Trump tweets, including ones that called Senate Democratic minority leader Chuck Schumer a clown, mocked America's intelligence agencies and gave credit to Internet outlaw Julian Assange, whose WikiLeaks site aided Russia's efforts to influence the 2016 election.

Michael D'Antonio

Biden's point is exactly right: If he is to be successful in his new role, Trump needs to make the shift from insurgent campaigner and tweeter to president of the world's superpower.

On January 20, as he takes the oath of office and the weight of the presidency falls on his shoulders, Trump will, for the first time in his life, be employed outside his family's business. At age 70, he will become accountable to the American people who will begin to learn whether this man with no experience in public service is up to the most demanding political job in the world.