What does Donald Trump's rule, “There can be only one No. 1, Two-Face.” mean?

Question

Maureen Dowd’s article in today’s (May 7th) New York Times that came under the headline, “Donald Trump or Paul Ryan: Who’s King of the Hill?” portrays the argument between Paul Ryan and Donald Trump, and wraps up with the following paragraph:

“For now,” Trump murmurs, taking out his hair spray for a spritz before he walks past the press octopus. “What I will remember is that you sabotaged me when I should have been savoring my success. And you should remember the No. 1 rule from “The Art of the Deal”: There can be only one No. 1, Two-Face.” (From The New York Times.)

I can’t understand what the last phrase, “There can be only one No. 1, Two-Face” means. Of course, there is only one No. 1. There cann't be two No. 1s, but what is “Two-Face,” and it’s not “Two faces”?

Answer 1

Perhaps better punctuation will help:

Trump murmurs... "What I will remember is that you sabotaged me when I should have been savoring my success. And you should remember the No. 1 rule from The Art of the Deal: 'There can be only one No. 1,' Two-Face."

In Dowd's fevered mind, Trump is talking to Ryan, whom he addresses as "Two-Face" after telling him about his rule There can be only one No. 1.

Trump means that Ryan may be the highest-ranking Republican elected official now, but that he [Trump] means to replace him [Ryan] in that role by becoming President.

"Two-Face" is a vocative and in the tradition of Trump, it's a derisive nickname. Two-Face means deceitful.

Answer 2

Two-faced is an insult meaning insincere and deceitful. Calling someone "Two-Face" most likely refers to this.

Also, see Two-Face, a villain from the Batman comics.

Answer 3

As @deadrat pointed out, the sentence could be better punctuated:

And you should remember the No. 1 rule from "The Art of the Deal": "There can be only one No. 1," Two-Face.

Now let's break it down.

Two-faced means "not honest or sincere." Trump uses "Two-Face" as a nickname for Ryan. He's implying that Ryan is two-faced.

So it might make the sentence a bit more clear to replace the nickname "Two-Face" with his actual name, "Ryan."

And you should remember the No. 1 rule from The Art of the Deal: "There can be only one No. 1," Ryan.

"Ryan" is being used in the vocative. It's indicating who's being addressed. If you were speaking to your friend Bob, you might say "I'm going to the store, Bob." In that sentence, "Bob" is unrelated to the statement "I'm going to the store." It's include in the sentence to emphasize that you are speaking to Bob.

Trump is adding "Ryan" to the end of the sentence to emphasize that he is specifically addressing Ryan, that Ryan is the person who should remember the No. 1 rule.

If it's still a bit confusing, you could reconfigure the sentence. All the following sentences are semantically the same:

Two-Face, you should remember the No. 1 rule from “The Art of the Deal”: "There can be only one No. 1."

You should remember the No. 1 rule form "The Art of the Deal," Two-Face: "There can be only one No. 1."

Answer 4

The other answers have addressed most of the aspects, but one.

A two-faced person is someone who (figuratively) has two faces. One that sweet-talks to you, and another that speaks evil of you behind your back.

And this definition predates the Batman comic!