I got this idea from reading a Matt Rognlie comment on a previous post. (But Matt may or may not agree with what I say here).
A. Suppose the government sells bonds, and finances those bonds by imposing a 10% sales tax on (say) milk.
B. Suppose the government sells transferable milk quotas, and sells just enough milk quotas that milk prices rise 10% above marginal costs.
C. Suppose the government sells transferable local monopoly rights to sell milk, and those local monopoly rights cause milk prices to rise 10% above marginal costs.
A, B, and C are basically [weasel word] all the same. For any tariff there's an equivalent quota, and quotas are just one way for a cartel to implement monopoly pricing. In all three cases the government is creating a marketable asset financed by a wedge between price and marginal cost. [Sure, it makes a difference if the demand for milk is uncertain, so one of those assets might be riskier than the others.]
That's basic micro. Now let's do some macro.
Some macroeconomists recommend using fiscal policy to help stabilise Aggregate Demand. In a recession the government should sell bonds, and use the proceeds to finance increased transfer payments (tax cuts) or increased government spending.
At its simplest, expansionary fiscal policy is the government dropping newly-printed bonds out of a helicopter, so anyone lucky enough to pick up a bond gets the transfer payment automatically.
Why not just drop transferable monopoly rights out of the helicopter instead? It should have the same effect.
In a infinitely-lived representative-agent model, neither helicopter bonds nor helicopter monopolies would have any macro effect (except for the supply-side effects of distortionary taxes/monopoly). Ricardian Equivalence says they wouldn't.
In an OverLapping Generations model, both helicopter bonds and helicopter monopolies would have the same macro effect. Both impose a "tax" on future generations and a transfer to the lucky current generation underneath the helicopter. This intergenerational transfer raises the natural rate of interest in an OLG model, which is just what the Keynesian (strictly, fiscalist) doctor recommends to cure a recession. The current generation feels wealthier, and is wealthier, so increases demand for goods at a given real interest rate.
The only argument I can think of for preferring helicopter bonds to helicopter monopolies is this microeconomic one: it is relatively easy to increase future taxes by the same percentage across all goods. It would be very hard, in practice, to increase the degree of monopoly power (as measured by percentage markup of price over marginal cost) by the same amount across all goods. So relative prices might be distorted more in the second case. (But don't microeconomists tell us that taxes should be higher on goods with relatively inelastic demand?)
Lengthening patent and copyright protection would be an expansionary fiscal policy, so might be a good idea if you wanted to increase output and employment in a recession.
[OK, as a practical policy recommendation, my tongue is very firmly in my cheek. And I admit I'm trolling lefty keynesians just a little. But as a teacher of macroeconomics (which is my job) I'm very serious. If you think you understand how fiscal policy works, in a Keynesian or New Keynesian model, you should be able to see the equivalence. Though macroeconomists who believe it is nominal wages rather than nominal prices that are sticky, and think that the AD curve slopes down (e.g. Scott Sumner) [Update: Scott says that's not exactly right], will object that increased monopoly power raises P, which moves us the wrong way along the AD curve in a recession.]