Why naval chronology should be checked before making a claim

Why is it often forgotten that the United States began building SSBNs before the Powers shootdown?

Because people often repeat remembered narratives without checking the chronology and technical details against sources.

The United States began building SSBNs before the Powers incident, so the chronology matters to the argument. The question broadens into a warning about relying on memory when technical systems have many marks and variants. A quick source check can prevent a confident claim from resting on the wrong date or specification.