What stops conservatives from recognizing that supply-side economics always fails?

In the loanable fund theory, interest rate affects saving as a supply of fund. An increase in rate,mean more saving. In the Keynesian model,the interest rate affects only the demand for money which is not for transition,but investment.

Interest rate then becomes an important factor both in IS and LM curve which can determine real GDP.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.