If Ronald Reagan were still in office, the base where these mini-subs, and every other NoKo base that housed any kind of submarine, would be large smoking holes in the ground, because it is clear that the NoKos cannot be trusted with those kinds of weapons and devices, and President Reagan knew how to petty dictators like Kim.
I highly doubt that President Reagan would have done that. Unlike Gaddafi (or whatever this week's spelling of his name is), lil'Kim has several thousand artillery pieces (some claim as much as 10,000) targeted at South Korea, in particular at Seoul. That is Kim's big stick ...not his 6-8 nuclear weapons, but the fact that in minutes he could raze Seoul without much that can be done to prevent it. Such a saturation attack could not be intercepted, and the artillery (both tube types and missiles) are dispersed across mountain ranges and impossible to get all at once unless the use of tactical nuclear weapons (and a good number of them) is authorized. I doubt Reagan would authorize that so close to China.
Anyways, what I believe President Reagan would do (that Obama would never do) is to authorize stepped up covert operations ....maybe you'd see some North Korean ships also hit 'old mines from the Korean war' or encounter 'such sad mechanical mishaps that caused them to sink.' The interesting thing about those mishaps is that they would, by pure coincidence ofcourse, always occur whenever N.Korea did something off. It can be so sad if a fuel oil depot, for instance, was to spontaneously combust ....
However, direct attacks on NoKo bases etc etc etc ....not unless Star Wars could also target thousands of shells and missiles streaming towards Seoul. The moment someone comes up with an answer for that (that can a. work and b. doesn't make things much worse, like a tac-nuke strike on NoKo would ....actually the country that would be protesting the most would be Taiwan, wondering what China's response towards IT might be) ....the moment someone comes up with an answer for those 10,000 arty pieces is the day Kim becomes the gelded b@stich he is! While he has his 6 nukes, and several tons of chemical (and most probably bio weapons), the use of those would totally destroy his regime. However the arty remains a credible threat.