Image copyright AFP Image caption Et tu, Pence?

Defined as a "star that leads or guides", does the word "lodestar" in the anonymously written op-ed attributed to a senior Trump official itself help reveal the writer's identity?

Some suggest the outlandish theory that it could be Vice-President Mike Pence, because he has used the word - otherwise rarely heard - with some regularity. Others argue that the word might be a ploy to divert attention from the real author.

Mr Pence's office has denied the suggestion, with his director of communications Jarrod Agen saying "our office is above such amateur acts" and that the New York Times "should be ashamed".

In the editorial, the writer, who claims to be "part of the resistance" inside the administration, refers to the late Senator John McCain as a "lodestar for restoring honour to public life and our national dialogue".

Here's Mr Pence saying the word in a series of other contexts.

The theory has sparked nearly 50,000 tweets since the op-ed was published, with much excitable speculation about the vice-president.

Journalist Dan Bloom searched for utterances of "lodestar" by other senior Trump officials, such as White House chief-of-staff John Kelly and Defence Secretary James Mattis, but found nothing.

Media playback is unsupported on your device Media caption Trump calls senior official's anonymous editorial "gutless"

Mr Pence by contrast had regularly been guided by lodestars, Mr Bloom found. They include "the first words of the UN charter 'to maintain international peace'" during a speech at the UN, an "unwavering belief in fundamental equality and dignity" at an awards dinner, "vigilance and resolve" alongside Japanese PM Shinzo Abe, a "balanced budget" in a 2011 address, and "established principles for sound analysis" in a 2001 comment.

However there are other theories, one being that the author could have been Mr Pence's speechwriter.

Another possibility is a "false flag" operation, in which the author is attempting to deceive Mr Trump by using words or a catchphrase that would normally be attributed to someone else - and in this case sow considerable further discord.

White House officials say this is a regular tactic when leaking information.

"To cover my tracks, I usually pay attention to other staffers' idioms and use that in my background quotes. That throws the scent off me," one White House official told the news website Axios.

Also arguing against the possibility of Mr Pence as the author is his own previous praise of Mr Trump.

Media playback is unsupported on your device Media caption What does Vice-President Mike Pence believe?

The hunt for the official's identity has spawned a few jokes, with one commentator suggesting that it could be Mr Trump's wife Melania - a reference to a speech she gave in 2016 which plagiarised elements of a previous address by former first lady Michelle Obama.

Meanwhile the news website Buzzfeed has published an anonymous op-ed entitled "I Am Part of the Resistance Inside the New York Times Opinion Desk".

"I work for the Gray Lady, but my loyalty is to the Take," it says, satirising what it says is a difference in outlooks between older op-ed writers and younger hires.

The New Yorker magazine has weighed in too with its own satirical take under the headline "Nation stunned that there is someone in White House capable of writing an editorial".