Bill and Melinda Gates issued their annual "state of the world" memorandum earlier this week. It's many pages long, so if you're interested in knowing what's essential, my excellent editor Diana Ransom posted the most startling highlights.

What struck me, personally, about the Gates letter wasn't what it contained but who it ignored. Last year's annual Gates letter was a huge broadside fired directly at President Donald Trump. Here are some excerpts:

"The world is not a safer place when more people are sick or hungry [but] President Trump proposed severe cuts to foreign aid."

"The America First worldview concerns me. It's not that the United States shouldn't look out for its people. The question is how best to do that. My view is that engaging with the world has proven over time to benefit everyone, including Americans, more than withdrawing does."

"The duties of the president of the United States is to role model American values in the world. I wish our president would treat people, and especially women, with more respect when he speaks and tweets."

In this year's letter, though, Trump doesn't make a single appearance. Instead the Gates spend hundreds of words on nuts-and-bolts philanthropy like the need for third world toilets and the disproportionate negative impact of bovine flatulence on world climate.

Important issues, certainly, but why the sudden absence of digs at Trump?

Well, as somebody who's interviewed both Bill Gates and Donald Trump (and spoken socially with Melinda before she married Bill), I believe I can provide some (semi-)informed speculation.

It can't be because the Gates have suddenly become frightened of Trump's tweets, since they've got enough money to buy Trump ten times over and still have enough to buy his cabinet of billionaires.

And it can't be because the Gates have had a change of heart and now agree with Trump. Indeed, the Gates continue to focus on the status and advancement of Africa, a region that Trump has dismissed as being full of "sh*thole countries."

And it can't be that Trump has secretly changed his views and informed the Gates of the change. Quite the contrary, it's impossible to imagine that a burger-loving, climate change denier like Trump would worry much about farting cows.

I strongly suspect that the Gates now ignore Trump because they no longer consider him all that important. From their lofty perspective, perhaps the Gates see clearly what the rest of us are beginning to sense--that Donald Trump is a paper tiger.

For all his bluster, Trump seems to be barely in control of himself, let alone the US government. While Trump can still do some damage,apparently the Gates have concluded it's a pointless waste of mental bandwidth to attempt to correct an incorrigible.