We calculated the rate of electron detachment from the ground state of H2– in a high-frequency linearly polarized laser field for various different intensities I and laser frequencies w. The calculations are performed within the Floquet framework in the Kramers-Henneberger frame. We find that at fixed frequency the rate of detachment decreases with increasing intensity, i.e., stabilization against photodetachment is found. In addition, the rate of detachment decreases as the frequency increases, illustrating the convergence to the high-frequency limit w®¥ in which photodetachment is absent. In the ground state of H2- the three widely separated electrons quiver along the same straight line parallel to the polarization axis with frequency w [Phys. Rev. Lett. 77, 3759 (1996)]. A comparison of the rates of detachment of the individual electrons shows that the middle electron is by far the most stable electron.