'The first is that spending will either be hurried and wasteful, or that it won’t come on stream until employment has recovered, and will therefore be inflationary.
The second is that deficit-financed government spending merely replaces spending by consumers and firms dollar for dollar; so-called 100 per cent ‘crowding out’. Critics often fail to point out that these two arguments cannot both be true. If government spending merely replaces private spending dollar for dollar, it does not affect total demand. As a result, it cannot be inflationary.
If “crowding out” is significantly less than 100 per cent, new spending will employ labour and capital that is now idle, and the earnings of workers and investors will re-ignite both consumer and investment spending. To be sure, stimulus programmes should target projects with productive potential. Economies from the US to China are in dire need of new physical and social infrastructure. But even “unproductive” projects are better than none at all if the alternative is to leave labour and capital unemployed.
And if stimulus spending for infrastructure comes into effect after the end of recession, when real resources and financial markets are re-employed, there are adequate monetary tools to contain such pressures. In other words, long-term plans for infrastructure planning can stand on their own merit.
So the key question is whether government spending that comes into action during recession is likely to crowd out new private spending, dollar for dollar. The answer depends on the extent to which real and financial resources are currently under-utilised.
“Real” crowding out occurs when labour and capital are already fully employed so that further spending exceeds capacity and leads to inflation. The logic of the harm done by inflation is well understood. But the logic of “financial” crowding out is less intuitive and more complex.
Simply put, financial crowding out results from rising interest rates when government deficits put pressure on bond markets. This kind of crowding out is most plausible in the US, which began the recession with the biggest deficit in world history. However, relative to national income, it is not nearly as large as that which Britain ran after the Napoleonic wars. And currently, the biggest as a percentage of national income is Japan’s: almost 200 per cent of its gross domestic product. It doesn’t seem to be crowding out private spending as the Japanese long-term interest rate is still only 1.5 per cent.
Nevertheless, skeptics argue that dramatic doubling of US deficits this year and beyond could leave little room for private sector borrowing. If the US deficit stifles rather than stimulates recovery of its private sector, prolonged worldwide recession is inevitable.'
The rest is here. BTW, Lipsey has written one of the all time best intro econ textbooks. A newer version is here.