A forcing axiom deciding the generalized Souslin Hypothesis

We derive a forcing axiom from the conjunction of square and diamond, and present a few applications, primary among them being the existence of super-Souslin trees. It follows that for every uncountable cardinal $\lambda$, if ${\lambda }^{++}$ is not a Mahlo cardinal in G"odel’s constructible universe, then $2^{\lambda }={\lambda }^{+}$ entails the existence of a ${\lambda }^{+}$-complete ${\lambda }^{++}$-Souslin tree.