Who did not see this coming as a result of the election of the Democrats? Anyone with intelligence since the main actions affecting the economy have all come from Trump and his administration. With the exception of the tax bill, which gave about 80% of the benefits to the ultra rich and large corporations and the remaining 20% to the working class (and led to an $80 billion increase in their overall tax bill if not more) the major factors affecting US economic growth have all been in the form of Executive Orders and Trump Tweets. As a matter of fact, the majority of bills passed by Congress, many of them bipartisan, have been blocked in the Senate by good ol Mitch even though members of his own party support them. Mitch's main goal in the Senate has been to block anything coming from Congress regardless of it's source or of it's effect on the country.
The negatives that are affecting the economy are:
The trade tariffs imposed by Trump, not only on China but on many other trading partners and the retaliatory tariffs imposed on the US in response.
The loss of market by farmers leading to billions of dollars in losses only some of which are being made up eventually through federal subsidies. Then of course you have to consider the loss if income for related industries such as food processing and trucking as well as shipping. With significantly fewer farm goods being produced due to no market for them sales of farm equipment have fallen creating a drop in demand for steel products. As a result blast furnaces have been idled with resulting layoffs due to low demand and uneconomic prices for steel.
The stock market which, although not the best measure of the economy, it does give an overall picture of what large investors expect to happen. During his first year in office the stock market continued growing at a record rate however since then it has been relatively flat with any gains offset by losses, some of a record nature. I noted that Trump has stopped bragging about stock marker performance like he frequently did during his first year. Much of the uncertainty is due to Trump and his ever changing trade and other economic policies as communicated through his many tweets.
One other thing, one of the first things Trump did when entering office was reduce regulations for companies. While this helped the stock market and the companies the overall effect of his actions are not so rosy. He eliminated financial regulations put in place to help prevent the financial actions responsible for the last recession. He also eliminated environmental protections placed on companies creating a situation where short term gain can equal long term pain to the taxpayers, both in economic and health related costs.