If we look at Germany's infrastructure policy, it has been driven by its mission-oriented focus on green infrastructure. This affects both innovation and infrastructure, old industries and new. The German steel industry, for example, has adapted to the policy by lowering its material content through a 'repurpose, reuse and recycle' strategy.

The globalized nature of production and innovation means that the benefits don't necessarily stay in the country where the investments are made.

If we look at Germany's infrastructure policy, it has been driven by its mission-oriented focus on green infrastructure. This affects both innovation and infrastructure, old industries and new. The German steel industry, for example, has adapted to the policy by lowering its material content through a 'repurpose, reuse and recycle' strategy.

We should be investing where the public returns are greatest - that is in innovation.

Mainstream economic theories popular in the last several decades have tended to downplay the government's role in markets and to increase skepticism about even that more limited role. Austerity, particularly in Europe, has added to the problem. It has not worked, even on its own terms.

Unfortunately, simplistic framing of problems leads to simplistic answers.

Too many politicians seem to reach for 'infrastructure' as the default answer to investment, as if roads and bridges were the answer to everything. Even the IMF and the World Bank seem to mainly offer infrastructure spending as an alternative to austerity, although they are right to focus on the need for investment.