More specifically strategy has an overall large plan and tactics take care of one specific goal. So a strategic plan to prevent the use of a harbor might be a

More specifically strategy has an overall large plan and tactics take care of one specific goal. So a strategic plan to prevent the use of a harbor might be a single strategic sized nuke. You could say the tactic and strategic levels merged into one. There's only one tactical move as part of that strategic plan. One call does it all. A nuclear tactical plan to prevent the use of a harbor might involve as a small part of the overall mission a nuclear torpedo to put a pesky submarine out of commission so a naval invasion can happen without being sunk by the sub. Or a nuclear artillery shell to clear a tank battalion guarding an approach to the harbor from your forces that'll take control of the harbor. Typically dropping a bridge with a nuke while retreating is rarely/never strategic, it's tactical as a tiny component of an overall retreat involving numerous tasks. Another characteristic is strategic "button pushing" rarely is authorized on the front line, but tactical "button pushing" is usually authorized at the front line. So M16s tend not to be strategic.