We won't know the natural rate until the generations go to Congress and do some overlapping

Think Again and Again About the Natural Rate of Interest

Says John Taylor, and reviews studies which point to extremely large error bands when estimating the natural rate.  What drives the uncertainty is the large and rising debt load that the CBO keeps showing us.  The overlapping generations are supposed to meet in Congress and make that debt bulge go down; they actually have to formally screw each other, mark to demographics.