  The observed orbital period distribution of cataclysmic variables (CVs), the
space density derived from observations, and the observed orbital period
minimum are known to disagree with theoretical predictions since decades. More
recently, the white dwarf (WD) masses in CVs have been found to significantly
exceed those of single WDs, which is in contrast to theoretical expectations as
well. We here claim that all these problems are related and can be solved if
CVs with low-mass white dwarfs are driven into dynamically unstable mass
transfer due to consequential angular momentum loss (CAML). Indeed, assuming
CAML increases as a function of decreasing white dwarf mass can bring into
agreement the predictions of binary population models and the observed
properties of the CV population. We speculate that a common envelope like
evolution of CVs with low-mass WDs following a nova eruption might be the
physical process behind our empirical prescription of CAML.
