We live better than our lowliest ancestors because we have learned to cooperate. The two sources of non-zero-sumness in our lives are market transactions (gains from trade) and love (chosen other-regardingness). Writing in today's NY Times Magazine, Adam Davidson notes "Donald Trump's obsession isn't just egotism. It reveals a dangerous and outmoded vision of the whole economy." The transactions ("deals") that Trump knows best are zero-sum. Davidson notes that coming out of the crony world of New York real estate, this makes some sense.
Yes, there are inevitably winners and losers from some international trade agreements (see my March 16 post) but the net gains are immense. Finding ways to assist the losers should start with the lower public schools. Those who nevertheless support the lower school status quo (except the standard call for more public moneys) are no more than hypocrites.
This is where Donald Trump and Bernie Sanders see eye-to-eye: the market economy is simply a place of conflict where I get the better of you or vice-versa. Mutually beneficial exchanges (which occur daily an uncountable number of times) are missing from their world.
Here is Scott Alexander's review or Trump's Art of the Deal. But it matters less whether Trump is real good or real bad at zero-sum deals. The problem is that these are the only trades he knows about.
More on zero-sum politicians.