Did Michigan Vote Against Trade?
Paul Krugman writes:
The Sanders win defied all the polls, and nobody really knows why. But a widespread guess is that his attacks on trade agreements resonated with a broader audience than his attacks on Wall Street; and this message was especially powerful in Michigan, the former auto superpower. And while I hate attempts to claim symmetry between the parties — Trump is trying to become America’s Mussolini, Sanders at worst America’s Michael Foot — Trump has been tilling some of the same ground. So here’s the question: is the backlash against globalization finally getting real political traction?It's certainly plausible that Donald Trump's and Bernie Sanders' strong performances in the Michigan primary are manifestations of a protectionist backlash. I was curious, and so using David Dorn's data on local declines in manufacturing and vote data from the Michigan Bureau of Elections, I checked.
The idea: To see if Trump and Sanders benefited from protectionist sentiment, I will compare their respective primary vote shares in a given county against how badly affected that county was by the decline of manufacturing employment.
The protectionist-backlash explanation of Trump and Sanders does not seem to hold up:
- Sanders' county-level vote share in the Democratic primary is not significantly correlated with that county's change in manufacturing employment, measured as a share of its working-age population. No matter how intense the local decline in manufacturing, Sanders won about half the Democratic vote.
- Trump's vote share in the Republican primary is in fact significantly positively correlated with that measure, meaning that he performed most strongly in areas where manufacturing's decline has been least important. Where manufacturing's decline was most intense, Trump received about 30 percent of the Republican vote, and where it was lightest, he received about 50 percent of the Republican vote.
Note: Dorn's data is actually at the "commuting zone" level, so I assumed that manufacturing declines were constant across counties within each commuting zone. I have data on 21 commuting zones and 83 counties in Michigan.
If you want to try to prove me wrong, I've made it easy for you: My pre-processed data are available here for download.