Based on a U(1) gauge theory of the Hubbard model on the triangular lattice, it is argued that a spin liquid phase may exist near the Mott transition in the organic compound κ-(BEDT-TTF)2Cu2(CN)3. In the spin liquid state, low energy excitations are fermionic spinons and an emergent U(1) gauge boson. Highly unusual transport properties are predicted due to the presence of a spinon Fermi surface. Despite rather good agreements with experiments, the stability of the spin liquid state has been continuously questioned because of the fluctuating gauge field which may destabilize the spin liquid state via confinement. In this talk, I will discuss how the presence of spinon Fermi surface can stabilize the spin liquid state against non-perturbative gauge fluctuations.