Which Administration Does What to Wages?

Esteemed Princeton economist, Alan Blinder, had an op-ed the other day in the NYT saying that inequality shrinks during the Democratic administrations, but grows during the Republican ones. Today, University of Chicago economist Casey Mullgan shows some evidence to the contrary. At least for the "gender gap" in wages (ie, the ratio of male to female earnings for different age/education profiles), inequality grew during the Democratic administrations and shrank during the Republican ones.

I take all of it with a grain of salt. I just have a hard time believing either of those correlations has anything to do with a sitting President, personally. But I'd need to read the studies. Mulligan's is part of a 2008 QJE paper, but Blinder's is based on a book by a political scientist.

I wonder if you couldn't use the 2000 Presidential outcome, where Bush basically won the entire presidency by 20,000-30,000 votes in Florida (basically winning by random chance, since it could've easily gone either way), in a regression discontinuity design to estimate the impact of administration on earnings differences?