A highly unpredictable trade war, as well as rattling every international ally, convincing nations across the world to choose other military platforms than ours because Trump could just turn it off at a whim, increasing risk of political instability leading nations to turn to other nations for investment. Our economy is a ticking time bomb under Trump.
Indeed, it's the terrible outlook on the economy that is leading the stock market down. The US is barreling towards recession, the continued flip flop on tariffs has cause business investment and projects to be frozen while everyone waits for certainty since they can't risk getting nuked by tariffs, the rapid and deep decline in trust of US made goods will ruin our exports and military base.