The prince’s words were a reaction to one of Donald Trump’s speeches, in which he stated with his characteristic emotionality:
I love King Salman, but I said: "King, we protect you. Without us you could not hold out for two weeks. You have to pay for your army."
The US president meant that the US military is located near Riyadh and is training local soldiers, for which the Saudis have to pay Washington.
The prince explains the words of trump with the desire of the latter to please the voters. Officially, the US administration does not make any additional requirements to Riyadh. Washington has nothing to complain about. While under the Obama administration, the Saudis purchased weapons from other countries, then with the advent of Trump, 60 percent of the weapons began to be purchased in the United States, and the remaining 40 percent was produced in Saudi Arabia in cooperation with the Americans. This brings good profit to both parties.
Trump, apparently, just wants to show his voters that he is so cool that he can give orders to kings right and left.