Conclusion
The point of this post is simple: the arguments concerning the endogenous nature of money and the irrelevance of the textbook multiplier do very little to challenge the case in favor of NGDP targeting (or inflation targeting, for that matter) and the general theoretical construct used by market monetarists. As I've shown, the case for NGDP targeting can be made (at least theoretically) using a quantity theory approach that is consistent with the endogenous nature of money.
Therefore, from a debating standpoint, those who support a functional finance approach to economic policy would be better served by focusing their efforts on challenging notions such as the natural rate of interest and in demonstrating the inadequacies of an approach to monetary policy whose monetary transmission mechanism relies largely on the portfolio balancing effect. While the issue of the natural rate is largely a theoretical problem (Does it exist? Can it be measured?), the question of the portfolio balance effect is essentially an empirical issue (Is the portfolio rebalancing effect substantial? Can the central bank control it for policy purposes?)
As for the bloggers and economists who think that post-Keynesians and MMT economists are wrong about the endogenous nature of money and its implications for central bank operations, I would suggest they review the work of Robert Hetzel. His take on these matters is in line with the post-Keynesian/MMT view.
Fictional Reserve Banking
Does the endogenous nature of money weaken the case for NGDP targeting?circuit