Cross-posted from: https://feddit.de/post/9912794
While a US commitment that NATO would not expand towards Russia was made during talks with the Soviets in 1990, and remains a topic of heated dispute, no undertaking was written into the treaty on German reunification.
They did. What the UK, the US and Russia(!) should do in case Ukraine is attacked, is to “seek immediate UN Security Council action” to provide assistance. Which the UK and the US did. Of course, that didn’t achieve anything because of the veto powers of the permanent UN Security council member Russia.