A serious war between the west and any major foreign power(s) will bring momentous volatility through reaction to unforeseeable events, price binges not well predicted by TA. Could be a time for guerilla trading, with dispersed small parcels of funds deployed to raid whichever instrument is moving fastest, with tight initial stops, then trailed close behind winning positions. In the early stages, reaction will be key, there will be little time for analysis or position development. No doubt brokers and TV commentators will be screaming that we should all buy Defence equities, sell Airlines, and accumulate Oil majors for the long-term - but they won't have a clue what to do and, anyway, when have they not being saying these things?
Overall, short-term trading for the agile private trader will continue, just with a brisker pace and arguably a little less exposure to the markets for the duration.
This would be a good time (peacetime) to re-read Sun T'zu.