Ukraine sabotaged it's security and military stability when it gave up it's nuclear weapons in 1994. A country should never surrender it's military leverage, regardless of promises and assurances from any party.
Prior to 1994, Ukraine had the 3rd largest nuclear weaponry in the world. That is after Russia and USA. However, promised that its territorial integrity would always be respected and that it's security is assured (by Russia, US and NATO), Ukraine gave up it's weapons.
Presently, what is happening is the consequence of such action.
Now the US government's reply to what is going on is that their prayers are with the Ukrainians. What happened to the support and security promised? If Ukraine had kept it's nuclear arsenal, Russia would definitely not be embarking on this expedition.
In like manner, do you know that the US is trying to convince Iran to give up it's nuclear arsenal too? Now seeing the example of Ukraine, the so called promised of security is a "heartfelt prayer" do you think Iran will submit to the request?
The abolition if a nation's military forces a d capability to wage war can only work for a few countries, not all.
Russia's opposition to Ukraine joining NATO might be somewhat understandable. The former is worried of the fact that western troops and weapons are placed in a country that borders them. Hence they see it as a threat. The US would also not be okay if Russian, European and Asian troops are placed in countries like Mexican or Canada. Russian feels threatened, hence the action. Nevertheless, Ukraine has the right to make it's own decisions based on its security. It's a sovereign country after all. It is beyond Russia to dictate who can or cannot join NATO.
Its a worry that Ukraine's decision 28 years ago is back to haunt them.
Hopefully the countries that promised them support would rise and do the needful.
The world's prayers are with Ukraine. 🙏