I will outline some ideas in recent work with D. Fisher and S. Hurtado establishing Zimmer’s conjecture for actions of general lattices in SL(n,R). This extends our earlier results for actions of cocompact lattices and of SL(n,Z). Problems involving escape of mass and “escape of Lyapunov exponents” arise when the lattice is not cocompact and I will outline some ideas used to avoid such behavior.