The authors have studied the stability of helical modes in a current carrying stellarator, ignoring the curvature of the axis and plasma pressure. They show that it is possible to fully stabilize a current column with a given arbitrary current value against both ideal and tearing modes by superimposing an external stellarator rotational transform with a sufficiently large value of its difference along the radius, |Δth| = |th(a) − th(0)|, in configurations of two types, namely with the total rotational transform increasing or decreasing with the radius. The value of the difference |Δth| needed for stabilization increases with the value of the total current.