I think, as a result
of earlier posts, that I can be pretty confident that I can answer
this question. But first some background. Although MMT has been
around for some time, it recently held its first international
conference and has in the last few years attracted a devoted band of
followers online. According to this article,
it has ‘rock star appeal’. In this post I just want to
concentrate on the core of MMT which involves fiscal policy, and not
talk about other ideas like job guarantees.
There are short and
simple explainers around (e.g. here),
but what these and MMT followers are typically not so good at is in
explaining exactly why and how they differ from mainstream
macroeconomics. To understand this, we need to go back to the 1960s
and 70s. Then there was a debate between two groups in macro over
whether it was better to use monetary policy or fiscal policy as an
instrument for stabilising the economy. I prefer to call these two
groups Monetarists and Fiscalists, because both sides used the same
theoretical framework, which was Keynesian.
To cut a long story
short the monetarist won that argument, although not quite in the way
they intended. Instead of central banks controlling the economy in a
hands off way using the money supply, they instead actively used
interest rate changes to control output and inflation. Fiscal policy
was increasingly seen as about controlling the level of government
debt. I have called this the Consensus Assignment, because it became
a consensus and because I don’t think there is another name for it.
The one or two
decades before the financial crisis were the golden years for the
Consensus Assignment, in the sense that monetary policy did seem to
be relatively successful at controlling inflation and dampening the
business cycle. However many governments were less successful at
controlling government debt, and this failure was termed ‘deficit
bias’.
MMT is essentially
different because it rejects the Consensus Assignment. It regards
monetary policy as an unreliable instrument for controlling the
economy, and MMT prefers to use fiscal policy instead. They are, to
use my previous terminology, fiscalists.
If you are always
using government spending or taxes to control the economy, you are
right not to worry about the budget deficit: it is whatever it needs
to be to get inflation to target. Whether you finance those deficits
by creating money or selling bonds is also a secondary concern - it
just influences what the interest rate is, which has an uncertain
impact on activity. For this reason you do not need to worry about
who will buy your debt, because you can create money instead.
The GFC exposed the
Achilles Heel in the Consensus Assignment, because interest rates hit
their lower bound and could no longer be moved to stimulate demand.
Alternative measures like QE really were as unreliable as MMT thinks
all monetary policy is. What governments started to do was use fiscal
policy instead of monetary policy to support the economy, but then
austerity happened in 2010 for all the reasons I explore at length
here.
Now we can see why
MMT is so popular. Austerity is about governments pretending the
Consensus Assignment still works when it does not, because interest
rates are at their lower bound. We are in an MMT world, where we
should be using fiscal policy and not worrying about the deficit, but
policymakers don’t understand that. I think most mainstream
macroeconomists do understand this, but we are not often heard. The
ground was therefore ripe for MMT.
Policymakers
following austerity when they clearly should not annoys me a great
deal, and I am very happy to join common cause with MMT on this. By
comparison, the things that annoy me about MMT are trivial, like a
failure to use equations and their wordplay. You will hear from
MMTers that taxes do not finance government spending, or that
spending comes first, but you will hardly ever see the government’s
budget constraint which makes all such semantics seem silly.
MMT is particularly
attractive because it does away
with the perennial ‘where is the money going to come from’
question. Instead it replaces this question with another: ‘will
this extra spending raise inflation above target’. As long as
inflation is below target that does not appear to be a constraint. In
the US right now interest rates are no longer at their lower bound,
but inflation is below target, so it appears to MMTers that the
government should not worry about how extra spending is paid for.
Of course having a
fiscal authority following MMT and a central bank following the
Consensus Assignment once rates are above their lower bound could be
a recipe for confusion, unless you believe what happens to interest
rates is unimportant. I personally think we have strong econometric
evidence that changes in interest rates do matter, so once we are off
the lower bound should we be fiscalists like MMT or should we return
to the Consensus Assignment? That is a question for another day.

