

The doctrine is called force majeure. Most contracts have a force majeure clause.
If an external factor makes a contract impossible as agreed, the contract can be made void under force majeure. This is very common, and suddenly applied tariffs would likely be covered by a force majeure clause because neither party were responsible for them.
This is a transcript of a meeting. Those are words that trump did say, but this screenshot is cropped deliberately to hide that fact.
This is one of the typical lies that trump is known to make in speeches. This isn’t a whitehouse staff member publishing those words as a written statement the office stands behind.