As Brexit demonstrated, knee-jerk reactions can be imprudent. Advising clients through myriad momentous events over the last 27 years tells us that it is generally necessary to take a deep breath and let the implications unfold.
This is yet more proof of the importance of diversification. Global events are too unpredictable (most experts were wrong on Brexit) to effectively jump in and out of the market. The answer isn't to try to avoid trouble. It is to diversify so you are never overexposed to the downside of one event.