From the Washington Examiner, of all places, we get this story:

A White House official told reporters that President Trump is "exhausted" just three days into his first trip abroad as president.

Trump was expected to say "Islamist extremism" during his speech to Muslim leaders in Saudi Arabia, but instead said "Islamic extremism."

When asked why Trump deviated from the prepared text of his speech, an administration official said Trump is "just an exhausted guy."

After the speech, Trump reportedly canceled his appearance at the Tweeps Forum. Ivanka Trump filled in for her father, speaking to about 400 people at the event.

The slip of saying “Islamic” extremism instead of “Islamist” extremism is significant, because “Islamist” doesn’t impute the extremism to all of Islam in the same way that “Islamic” does. This was a major goof to make in front of the King of Saudi Arabia and his advisers and guests. To attribute it to exhaustion is tantamount to saying that Trump simply doesn’t have the stamina to be president.

Then later in the day, this happened:

Don’t you think he looks tired?