If I was organized enough to send Christmas cards, I would take Richard Rahn off my list. I do one blog post to call attention to his Washington Times column and it seems like everybody in the world wants to jump down my throat. I already dismissed Paul Krugman’s rant and responded to Ezra Klein’s reasonable criticism. Now it’s time to address Derek Thompson’s critique on the Atlantic’s site.

At the risk of re-stating someone else’s argument, Thompson’s central theme seems to be that there are many factors that determine economic performance and that it is unwise to make bold pronouncements about Policy A causing Result B. If that’s what Thompson is saying, I very much agree (and if it’s not what he’s trying to say, then I apologize, though I still agree with the sentiment). That’s why I referred to Reagan decreasing the burden of government and Obama increasing the burden of government — I wanted to capture all the policy changes that were taking place, including taxation, spending, monetary policy, regulation, etc. Yes, the flagship policies (tax reduction for Reagan and so-called stimulus for Obama) were important, but other factors obviously are part of the equation.

The biggest caveat, however, is that one should always be reluctant to make sweeping claims about what caused the economy to do X or Y in a given year. Economists are terrible forecasters, and we’re not even very proficient when it comes to hindsight analysis about short-run economic fluctuations. Indeed, the one part of my original post that causes me a bit of regret is that I took the lazy route and inserted an image of the chart from Richard’s column. Excerpting some of his analysis would have been a better approach, particularly since I much prefer to focus on the impact of policies on long-run growth and competitiveness (which is what I did in my New York Post column from earlier this week  and also why I’m reluctant to embrace Art Laffer’s warning of major economic problems in 2011).

But a blog post is no fun if you just indicate where you and a critic have common ground, so let me identify four disagreements that I have with Thompson’s post:

(1) To reinforce his warning about making excessive claims about different recessions/recoveries, Thompson pointed out that someone could claim that Reagan’s recovery was associated with the 1982 TEFRA tax hike. I’ve actually run across people who think this is a legitimate argument, so it’s worth taking a moment to explain why it isn’t true.

When analyzing the impact of tax policy changes, it’s important to look at when tax changes were implemented, not when they were enacted (data on annual tax rates available here). Reagan’s Economic Recovery Tax Act was enacted in 1981, but the lower tax rates weren’t fully implemented until 1984. This makes it a bit of a challenge to pinpoint when the economy actually received a net tax cut. The tax burden may have actually increased in 1981, since the parts of the Reagan tax cuts that took effect that year were offset by the impact of bracket creep (the tax code was not indexed to protect against inflation until the mid-1980s). There was a bigger tax rate reduction in 1982, but there was still bracket creep, as well as previously-legislated payroll tax increases (enacted during the Carter years). TEFRA also was enacted in 1982, which largely focused on undoing some of the business tax relief in Reagan’s 1981 plan. People have argued whether the repeal of promised tax relief is the same as a tax increase, but that’s not terribly important for this analysis. What does matter is that the tax burden did not fall much (if at all) in Reagan’s first year and might not have changed too much in 1982.

In 1983, by contrast, it’s fairly safe to say the next stage of tax rate reductions was substantially larger than any concomitant tax increases. That doesn’t mean, of course, that one should attribute all changes in growth to what’s happening to the tax code. But it does suggest that it is a bit misleading to talk about tax cuts in 1981 and tax increases in 1983.

One final point: The main insight of supply-side economics is that changes in the overall tax burden are not as important as changes in the tax structure. As such, it’s also important to look at which taxes were going up and which ones were decreasing. This is why Reagan’s 1981 tax plan compares so favorably with Bush’s 2001 tax plan (which was filled with tax credits and other policies that had little or no impact on incentives for productive behavior).

(2) In addition to wondering whether one could argue that higher taxes triggered the Reagan boom, Thompson also speculates whether it might be possible to blame the tax cuts in Obama’s stimulus for the economy’s subsequent sub-par performance. There are two problems with that hypothesis. First, a substantial share of the tax cuts in the so-called stimulus were actually new spending being laundered through the tax code (see footnote 3 of this Joint Committee on Taxation publication). To the extent that the provisions represented real tax relief, they were much more akin to Bush’s non–supply side 2001 tax cuts and a far cry from the marginal tax-rate reductions enacted in 1981 and 2003. And since even big tax cuts have little or no impact on the economy if incentives to engage in productive behavior are unaffected, there is no reason to blame (or credit) Obama’s tax provisions for anything.

(3) Why doesn’t anyone care that the Federal Reserve almost always is responsible for serious recessions? This isn’t a critique of Thompson’s post since he doesn’t address monetary policy from this angle, but if we go down the list of serious economic hiccups in recent history (1974-75, 1980-82, and 2008-09), bad monetary policy inevitably is a major cause. In short, the Fed periodically engages in easy-money policy. This causes malinvestment and/or inflation, and a recession seems to be an unavoidable consequence. Yet the Fed seems to dodge any serious blame. At some point, one hopes that policy makers (especially Fed governors) will learn that easy-money policies such as artificially low interest rates are not a smart approach.

(4) Thompson writes, “Is Mitchell really saying that $140 billion on Medicaid, firefighters, teachers, and infrastructure projects are costing the economy five percentage points of economic growth?” No, I’m not saying that and didn’t say that, but I have been saying for quite some time that taking money out of the economy’s left pocket and putting it in the economy’s right pockets doesn’t magically increase prosperity. And to the extent money is borrowed from private capital markets and diverted to inefficient and counter-productive programs, the net impact on the economy is negative. Thompson also writes that, “Our unemployment picture is a little more complicated than ‘Oh my god, Obama is killing jobs by taking over the states’ Medicaid burden!’” Since I’m not aware of anybody who’s made that argument, I’m not sure how to respond. That being said, jobs will be killed by having Washington take over state Medicaid budgets. Such a move would lead to a net increase in the burden of government spending, and that additional spending would divert resources from the productive sector of the economy.

The moral of the story, though, is to let Richard Rahn publicize his own work.