In addition to trying to start a nuclear arms race, Donald Trump is violating the "one President at a time" norm, too. As if he has any regard for norms. (He doesn't)

In a series of tweets, it's obvious he's trying to undermine President Obama's final days in office by pretending he's already the President.

On Friday, he started tweeting again, and unfortunately they're not tweets we can ignore.

First, we have this in response to the U.S. abstention at the United Nations on the Israeli settlement vote.

And then we have this, sparked by Russian President Vladimir Putin's troll of Democrats and Hillary Clinton.

Never in my lifetime did I think I would see a United States President-elect side with an autocratic President of an adversarial country. Never in my lifetime did I think we would have a President-elect who would side with someone who actually kills journalists and those who disagree with him.

But here we are, with a President-elect who has absolutely no respect for any democratic norms, who is intent on waving his penis around and pretending he's already President. Someone who sides with the Russian president over his fellow Americans while pretending he wants to be the President of all Americans.

Utter bullsh*t.

And the thing is, as much as we want to ignore him, we cannot, as Professor Jay Rosen notes: