It supports something that I've believed, but not really had strong evidence for, namely, that Republican economic policies increase inequality. However, above and beyond that, it suggests that Democrats are actually more effective with the economy overall. Here, the author details two key facts emerging from the economic data:
I call the first fact the Great Partisan Growth Divide. Simply put, the United States economy has grown faster, on average, under Democratic presidents than under Republicans.
The stark contrast between the whiz-bang Clinton years and the dreary Bush years is familiar because it is so recent. But while it is extreme, it is not atypical. Data for the whole period from 1948 to 2007, during which Republicans occupied the White House for 34 years and Democrats for 26, show average annual growth of real gross national product of 1.64 percent per capita under Republican presidents versus 2.78 percent under Democrats.
The second big historical fact, which might be called the Great Partisan Inequality Divide, is the focus of Professor Bartels’s work.
It is well known that income inequality in the United States has been on the rise for about 30 years now — an unsettling development that has finally touched the public consciousness. But Professor Bartels unearths a stunning statistical regularity: Over the entire 60-year period, income inequality trended substantially upward under Republican presidents but slightly downward under Democrats, thus accounting for the widening income gaps over all. And the bad news for America’s poor is that Republicans have won five of the seven elections going back to 1980.
Now, some caution in interpreting these results is in order. Correlation is not causation, and we're dealing with something enormously complex over a relatively short time-span of about 60 years. (Some possible complications: perhaps it takes several years for a president's policies to have any significant impact on the economy; and what about the role of Congress and which party controls it?) Plus, there are many other ways than economic growth that one may use to assess the welfare of a nation.
It may be a stretch to say that Democrats are generally better for the economy, but certainly they are at least comparable, contrary to what Republicans claim. Plus the evidence is quite strong that they are better for reducing inequality, which I would argue is itself valuable because greater equality means greater stability. (And, as Spinoza tells us, stability is the foremost virtue of a good state.)
I may have to check this book out. While I'm not a Democrat, I do tend to vote Democratic, and this is certainly useful information to have.