Nixon used to do that. Preface everything with “let me be clear,” “let me be crystal clear”, “let me be totally, completely, spotlessly, absolutely, positively, CRYSTAL clear”... He also used to say “As I’ve said before” a great deal too.
Funny you should mention Nixon. Had the ‘Rats not stolen the election of 1960 (which Nixon actually won), the Soviets would never dared their Cuban Missile gambit, because they had taken the measure of Nixon as Vice President, saw his resolve in the ‘Kitchen Debate’ in Moscow vs. Khrushchev, and his coolness in a personal crisis when his limousine was attacked by rioters in South America. They knew not to eff around with Nixon.
But with JFK installed into the Presidency thanks to vote fraud in Illinois and Texas, the Soviets perceived him as weak, and they chose to test him. It was only through sheer luck that we avoided a nuclear exchange with the Soviets, but the price was an American pledge not to overthrow that sonuvabitch Castro. JFK wrote off the Cuban people and that is why we still have a Communist tyranny 90 miles from our shores.
How this Korean situation will turn out with a goofy undocumented Kenyan in the White House that has LESS experience than even the Buffoon from Plains Georgia, Jimmy STP Carter, remains to be seen.
Prediction: it’s not going to turn out well for us.