I think too much spending is like coke, its awesome when your high, but you can stay high forver and the longer you try to the worse it is when you come down
Spending is kind of like that but not investing.
When build a bomb. Yea there is a temporary job increase. After you drop that bomb though you get nothing back.
Now you rebuild (which has to be done at some point all we are doing is putting it off) and update your critical infastructure. That investment is going reused by the citizens over and over.
For exampe when the United States built the transcontinental railroad. It set the staging ground for the industrial revoluation in the United States. We recovered every single dollar we went on the transcontinental railroad and then some.
Also the trying to stay high forver point does not necessarily apply. If demand in the economy picks up you will not have to spend as much plus you will be getting more revenue back in return.
You say your initial investments generates X amount of new jobs. Well those people with new jobs are going spend their money on goods and services in the economy. When that happens business are going to have to meet that increased demand. They are going hire more people, buy more raw materials, and that means more delivery drivers. So that means more new jobs that means more people spending money and the cycle contiunes.
Now if you cut back when their is no growth. Then that jobs loss means less demand. Less demand means less hiring or even law offs. That means even less demand. Suddenly the cycle is headed the wrong direction.
Also when less people are working what does it mean? Less taxes. Less taxes mean higher deficits and if you are following the austerity plan that means more cutting back. Hence more job loss, less demand, more job loss, less taxes and the cycle continues.
The narrative in the United States national media has been all about the debt. We need to be talking about jobs. If the 1990s taught Americans anything is that the fastest way to shrink the deficit is a booming economy.