What historical events from the 20th-21st century can be compared to what is happening in Ukraine?

In 2022 Russia invaded Ukraine. The US and many other Western countries have said they try to hold out on war, and in the meantime supply Ukraine with weapons, vehicles, and other goods. I am wondering if there is a historical event that is similar to this situation, where a Western power is actually open and truthful about sending weapons to a country that is currently being attacked by a rival power who wishes to take over their country.