The stock market priced in a long Trade War with China this week with a 1.5% decline in the S&P 500, at it’s low on Thursday. Or so they said on TV. In the old days, it would take a few days for information like that to become the consensus opinion.
Macro trends can run for a while, but they can also experience a quick end. Elections (Brexit, US Presidential Election) can cause the most powerful reversals in markets.