As the government’s case against U.S. Sen. Robert Menendez moves toward a trial, both sides in the case will be honing arguments about the true meaning of friendship.

Menendez’s contention that the corruption charges against him are unfounded because his longtime friendship with Florida eye doctor Salomon Melgen is genuine is his best defense in the case, according to some lawyers, but whether it gains traction will depend on the details of the friendship and how a jury reads the issue.