Here is the interchange about the "promise".
Prankster:
"When, in the early nineties, Secretary of State Baker promised Gorbachev not to spread, not to expand NATO; but this would be completely wrong, especially with the threat that Russia poses now."
President Dubya Bush:
"Yeah, that's right. That's right. Listen, times change. Baker was, ah, you know he was the Secretary of State for my dad, years ago. And so, and the United States must be flexible, adjusting to the times." And that's why you are finding such strong support for your country now.
Prankster:
"No, I mean, I mean, it doesn't matter what Baker really promised Gorbachev in past. We have to see what is going on now. "
President Dubya Bush:
"That's right."
Of course, what Baker may have "promised" in an oral exchange with Gorbechov, is not in any way binding on the United States or Russia. Treaties have to be written, so they are clearly understood. They have to be confirmed by the Senate.
So, it appears former President Bush was agreeing with the obvious. It does not matter what former Secretary of State Baker might have said, or not. We have to deal with the invasion of Ukraine in the here and now.
If you doubt my transcript, go to the video file and listen for yourself. If you find discrepancies, please correct me.
At most, it is "morally binding" on the Administration that actually made that promise, and would have been understood as auch. George H.W. Bush absolutely had the authority not to deploy U.S. troops in East Germany, and not to expand NATO, for as long as he was President. He was true to his word, and the Soviet withdrawal from East Germany was peaceful and smooth. The promise was fulfilled.
If Bush and/or Gorbachev wanted to take it beyond a personal promise, and bind the U.S. into the future, they both knew how that had to be done, and didn't do it.
What amazes me about this is that the same people who are arguing that we should be bound forever by a verbal promise made in 1990 are very likely the same people who (quite rightly) argued that future administrations had no obligation to abide by the Kyoto protocols or Paris Agreements because they were never submitted to and ratified by the Senate.