It’s not shifting accountability. After WWII, France demanded that its colonial holdings, including French Indochina, be returned to it as a requirement for it joining NATO. The Vietnamese were not interested in returning to French colonial rule. This kicked off a decade-long war between the two that the French lost. The US had advisors to the southern Vietnamese during that time, and rather than fully pulling out, increased their presence as they tried to manage the void left by the French. This spiraled into the Vietnam War.
The US is on the hook for its decisions. But Europe doesn’t get off the hook for its own.