It depends. But I will argue that what it depends on is probably different from what most people think is important.
When I was young, I looked at this issue in partisan terms. Divided government is good (I thought) when the party I oppose holds the presidency, and unified government is good when my preferred party holds the presidency. I suspect this is a fairly widespread view, especially among better educated voters. But I now think this is wrong.
I have come to the view that the deciding factor is not “which party occupies the presidency”, but that the optimal outcome depends on the answer to this question:
Is this an era of relatively good governance, or an era of relatively bad governance?
If we are operating in an era where governments are pursuing useful reforms such as deregulation, privatization, freer trade, fiscal responsibility, and tax reform, then a more powerful central government can be (and I emphasize that it can be) a good thing. When we operate in an era of socialism and nationalism, more government power is generally a bad thing.
Since most of the readers of this blog live in the US, I won’t use an American example to make this point. It’s too difficult to see beyond our own personal political biases. Instead, I would ask you to look across the pond and reflect on recent British history.
They have had three relatively long periods in which mainly one party ruled. The Conservatives governed from 1979 to 1997, then Labor from 1997 to 2010, and then the Conservatives governed again until last summer’s election. What do we notice from these eras?
1. Governments often do better in the initial phase. They come to power with a plan to fix the shortcomings of the previous government, and often do a number of useful things during the early part of their term. Then the petrol runs out and the quality of policymaking deteriorates.
2. Governments tend to have better policymaking when the global zeitgeist moves in a “neoliberal” direction (say until 2007), and less effective policymaking when the world moves in an illiberal direction.
I certainly won’t tell people how to vote, and in a presidential year you can’t even know with certainty whether your vote would lead to a unified or divided government. (In midterm elections, the voters know.) But one thing to think about might be whether we are in an era of good government or bad government. Is the political zeitgeist moving towards balanced budgets and supply-side reforms, or is it moving in the opposite direction? How much confidence do you have in the policymaking process of contemporary America?
One last point. I don’t rule out the possibility that divided government is more often good than bad. That largely depends on how much ‘activism’ you prefer. My own view is somewhat hostile to government activism, so my preference is for divided government. In this post I’m just trying to describe when each outcome is relatively more importantly, not necessarily what is best in an absolute sense. If I were in favor of government activism, I might lean toward the view that unified government is generally best. Yet I think people tend to underestimate the importance of the spirit of the times, the importance of whether we are in an era of relatively good governance or an era of relatively bad governance.