From Kevin Williamson at National Review – Real Trouble:

If policy-makers in Washington could be sure that their policies would consistently, reliably, and predictably have the desired effect, then there would be no economic issues in politics, because there would be steady growth, low unemployment, rising wages, rising profits, no recessions, no real inflation, etc. We don’t have non-optimal economic problems because people in Washington are being bought off by special interests (ones that apparently want recessions and high inflation, whomever those might be), or because they are wicked and don’t care about the good of the people. We have non-optimal economic problems because people in Washington don’t actually know what to do with any degree of specificity, because there are competing priorities, because real-world events change more quickly than policy-makers can account for, and because the world is complex and unknowable.

Despite all this, for some reason, the political incentives encourage those in power to lie and pretend to omnipotence rather than to tell the truth about their limited knowledge and modest real-world capabilities. But there are some things that really do work in a reliable and consistent way, and one of those is maintaining a reliable and consistent economic-policy environment. I care less about whether the top personal income-tax rate is 39 percent or 36 percent than I do about whether we can pick one and stick to it for a few decades at least, and, more generally, about ensuring that we do not undertake big and disruptive changes to the policy environment without real consensus and careful deliberation. But instead of that conservative approach, every time a party achieves a temporary majority in Congress or control of the White House, its leaders promise revolution and a radical reordering of taxes, regulations, incentives, terms of trade, and everything else they can think of. I suspect that one of the poor results of that erratic approach is documented in those disappointing charts above.