The 2017 tax reform bill [1] "seeks to address some widely acknowledged issues with corporate taxation, and takes some steps toward broadening the tax base, in part by reducing the incentive to itemize deductions." It was the first substantive piece of tax reform since 1986, and while there are many things to criticize, it at least started to align US corporate tax rates with those in other developed countries.
One of the significant changes that the tax reform brings is an increase in the cost of capital raised in the form of debt. That is a good thing. The deductibility of interest on corporate debt creates an enormous distortion that causes firms to favour leverage, which leads to greater instability in the economy. Should interest be tax deductible? Well, whether or not you think it should be, it is. And so reducing the corporate tax rate makes that deduction less valuable than it was before.
The tax reform is hugely regressive in reducing the top marginal tax rates for high income earners. That is a giant negative IMHO, because wealth and income inequality are a huge problem in American society. So, personally, I believe the only good from the tax reform is on the corporate taxation side by, effectively, making things a little more efficient than they were before.
Other things that I think were a positive:
1. Rejecting Chinese firms' from the 5G network build-out. His diplomacy and trade policy were really random, but this was one move that worked out well.
2. Operation Warp Speed. While Hillary Clinton likely would have done a FAR, FAR better job of handling the pandemic overall, credit is due to Trump for getting behind the advanced purchase of billions of dollars worth of vaccines before they were even approved.
3. Greatly increasing the standard tax deduction for low income earners. "For income earned in 2020, single people pay no income tax on their first $12,400, heads of household on their first $18,650, and married couples on their first $24,800." [2]
Again, it's too bad that all the insane stuff he did and all the things he neglected will overshadow his accomplishments. History will likely judge Trump harshly, which I think is richly deserved.
[1] https://pubs.aeaweb.org/doi/pdf/10.1257/jep.32.4.73
[2] https://www.theatlantic.com/ideas/archive/2020/12/the-things...