Is now the time to invest with markets potentially collapsing?

Current events seem to indicate market stock prices may trend downward given certain trade wars and what not. Not here to discuss politics, but purely the impact this has on markets and the opportunities this presents.

When markets are down, entry prices for stocks and investments are great. For those of us that saved money, do these factors not indicate it is a good time to begin buying? Or are there other variables I’m not accounting for?

I’m asking this as a general strategy, obvious individual circumstances may differ. But would you say that current markets going down signify opportunity to grow the portfolio?