Some comments, some answers
Astrology requires an event as a basis for a chart. An "event" can be a birth chart for a person or for a country, but it can also be a current event which establishes something new or out of character. Let me give a few examples:
A new person comes into your life tomorrow at 1:15 pm. You don't know your own birth time or any information about this other, new person. You can use the date and time of this meeting to cast a chart and use it as a relationship chart -- into which you can, if you know how, read yourself, read the other person, and read the possible interactions between you both. You can also look at transits and see what is likely to happen in the following days, weeks and months that could influence this meeting.
The infamous "9-11" event was something that was totally new, different, and marked a mind/social shift for the country and for others around the world. The charts were quite telling. However, the chart for this event did not seem to have a tie-in with other events such as the years-earlier garage bombing at the trade center, the attack on the USS Cole, the Madrid train bombings, etc. But, the Saturn-Pluto conjunction a couple of decades back (these two planets can be interpreted as harsh, anti-social, cruel acts) provides a basic pattern to which all of the international terrorist events are clearly tied. Again, you have to know astrology well to do this and easily see it.
So, if you have a base chart, you can do astrology. If not, no astrology as such.
As for the Tarot, ask a question (any question), get an answer. Well, not in every case. Timing and future likelyhood (not just a general possibility) can not generally be obtained thru the Tarot -- but Astrology excells at future prediction. However, within its scope of applicablity, the Tarot is quick and almost universally applicable. That said, there are a few conditions. You have to know how to properly phrase a question, you have to use a spread that reflects the components of the answer you seek.
You asked about answering a question about North Korea. If you know nothing about North Korea's society, political and military structure, the way the populace has adapted their culture to fit the harsh reality of the regime in power, then it might be hard to construct anything more than a simple spread or ask a simple question. On the other hand, since birth times are known for these countries, astrology can answer almost anything about them.
So, each is good for what it does best. Tarot is simpler and quicker to use, astrology is more comprehensive, accurate and future timing capable. You use the tools that best fits. Dave