George Mathew, chief executive of Kespry, shows a drone to President Trump during the American Leadership in Emerging Technology event at the White House in 2017. (Jabin Botsford/The Washington Post)

During his first Cabinet meeting of the year on Wednesday, President Trump offered an unexpected defense of his views on border security.

A wall was needed, he argued, because you couldn't use technology alone, like drones, to prevent illegal border crossings. How could we be confident in that?

"I know more about drones than anybody," Trump said.

This is possible, I suppose. Perhaps Trump has spent an inordinate amount of time studying unmanned aircraft during his tenure in the White House, or, perhaps, he brought to the job years worth of analysis on the subject. It just seems as though perhaps it’s hyperbolic. Even if we constrain the comment to the context in which it was offered — the use of drones to patrol the border — it seems unlikely that Trump is the foremost authority on the subject in the world.

Close Trump watchers will recognize the format of this assertion that Trump knows more than anyone about topic X. He's used it frequently, fitting with his tendency toward hyperbole in all things, especially himself. It is high time, though, that we document all of Trump's expertises, given how frequently a president is called upon to exercise his judgment on important issues. We should know when Trump is offering an opinion that derives from his position as the preeminent authority on the subject.

So, an index of those things on which Trump is the leading expert — or those subjects on which he has identified others as unmatched global authorities. (The foremost authority on Trump quotes is Factba.se, from which most of this was drawn.)

Agriculture. Qualified foremost authority: Agriculture Secretary Sonny Perdue.

"You know more about agriculture than any human being that I've ever spoken to," Trump said of Perdue at an event in Georgia last October.

Bin Laden, Osama. One of the foremost authorities: Donald Trump.

In an interview with Breitbart radio in November 2015, Trump claimed authority on the terrorist leader.

“I was against the war in Iraq, okay? And I was right about it,” Trump said, untruthfully. “You also know I predicted that Osama bin Laden was coming to the United States, because I knew a lot about it, and I know more about it than most, believe me, and I’ve been given credit for it.”

Booker, Cory. Foremost authority: Donald Trump.

Presuming that Sen. Cory Booker (D-N.J.) is the de facto expert on himself, anyone who knows more than Booker would assume that title. And so:

Borders. Qualified foremost authority: Former White House chief of staff John F. Kelly.

“You know more about borders, I think, than anybody,” Trump said to Kelly at a meeting in May.

Borders. Foremost authority: Donald Trump.

That according to former Maricopa County sheriff Joe Arpaio who, Trump claimed in July 2016, once gave him that praise.

"I just want you to know that I'm endorsing you because you know more about this stuff than anybody," Arpaio told Trump, according to Trump. "You know more about this stuff than people doing it for 25 years. You get it."

Campaign contributions. Foremost authority: Donald Trump.

I know more about contributions than anybody,” he said in an ABC News interview during the campaign.

Courts. Foremost authority: Donald Trump.

"I know more about courts than any human being on earth. Okay?" he claimed at a rally in Texas in November 2015.

Debt. Foremost authority: Donald Trump.

“Nobody knows more about debt than I do,” Trump said in an interview in 2016.

Drones. Foremost authority: Donald Trump.

As above.

Facebook, power of. Foremost authority: Donald Trump.

At a rally in South Carolina, Trump said: I understand the power of Facebook maybe better than almost anybody, based on my results, right?”

Guns. Qualified foremost authorities: Trump’s sons Eric and Donald Jr.

Trump made this bold claim at a National Rifle Association convention.

“I’ve been a member for a long time, and my boys are members, and they’re much better shooters than I am, I’ll tell you,” he said. “They know more about guns than any — I don’t know, there may be two or three people in this room, but believe it or not, not many.”

H-1B and H-2B Visas. Foremost authority: Donald Trump.

Nobody knows the system better than me,” Trump said during a debate. “I know the H-1B. I know the H-2B. Nobody knows it better than me.”

Infrastructure. Foremost authority: Donald Trump.

Another claim from the campaign trail in 2016: Nobody in the history of this country has ever known so much about infrastructure as Donald Trump.”

Law. Foremost authorities: Police chiefs.

Speaking to leaders at a convention of the Major Cities Chiefs Association, Trump declared that “you know more about law than anybody, law enforcement.”

Left, the political. Qualified foremost authority: Donald Trump.

"I think I know more about the other side than almost anybody," Trump said at a campaign event in November 2016.

Money. Foremost authority: Donald Trump.

I understand money better than anybody,” Trump said in defense of low fundraising totals in mid-2016.

NAFTA. Foremost authorities: People in Maine.

“You people know more about NAFTA than anybody, okay?” he said during a campaign event in that state in March 2016. “Anybody. 'Cause you know how you were stripped with NAFTA, which was a disaster.”

Nuclear, horror of. Foremost authority: Donald Trump.

People who get good TV ratings. Foremost authority: Donald Trump.

Politicians. Foremost authority: Donald Trump.

A rally in March 2016, Trump claimed to “know more about politicians than anybody.”

Renewables. Foremost authority: Donald Trump.

Speaking to Fox News’s Sean Hannity in 2016, Trump said, “[L]ook, I know more about renewables than any human being on earth because I understand it from — you know, from ..." The transcript for the conversation then reads “[INAUDIBLE].”

Security. Foremost authorities: Police chiefs.

Also at the Major Cities Chiefs Association convention, Trump defended his ban on migration from heavily Muslim countries by telling the audience that it “was done, very importantly, for security — something you people know more about than all of us.”

Shale. Foremost authorities: Pennsylvanians.

“[Y]ou know more about shale than anybody, right here in Pennsylvania,” Trump told an audience at an event in that state shortly before the 2016 election. He was referring to energy production from hydraulic fracturing, a shift that drove a huge spike in production in Texas, Oklahoma and North Dakota.

Steelworkers. Foremost authority among politicians: Donald Trump.

At a rally in New Hampshire in 2016, Trump was direct.

“I know more about steelworkers than anybody that’s ever run for office,” Trump claimed.

Taxes. Foremost authority: Donald Trump.

In an interview with the New York Times in 2017, Trump claimed expertise on this subject.

“I know the details of taxes better than anybody. Better than the greatest C.P.A.,” he asserted. He went on to modestly claim that he knew “the details of health care better than most.”

Tax reform. Foremost authorities: Business leaders who attended a White House meeting on the subject in October 2017.

“You are leaders of this country and certainly leaders on this subject, and you know more about it than anybody,” Trump said to the group that included the heads of the U.S. Chamber of Commerce, the National Association of Wholesale-Distributors and the Small Business and Entrepreneurship Council.

Technology overall. Foremost authority: Donald Trump.

Trade. Foremost authority: Donald Trump.

Nobody knows more about trade than me,” Trump said at that rally in March 2016. (He was comparing himself with Mitt Romney.)

Wall Street bankers. Foremost authority: Donald Trump.

Trump spoke with former NBC host Matt Lauer on the “Today” show in 2016. Lauer said, “You’re a guy who said you know the Wall Street bankers better than anyone.”

“Better than anyone,” Trump agreed.

Wedges. Foremost authority: Donald Trump.

The context, in an interview with the Wall Street Journal last year, was if North Korea was attempting to drive a wedge between the United States and South Korea.

“I know more about wedges than any human being that’s ever lived,” Trump said, “but I’ll let you know.”