Constraints on the tensor-to-scalar ratio r and the amplitude of the polarized dust power A_dust within a model with free lensing potential amplitude A_lens. The two-dimensional likelihood contours at 68% and 95% are forecasted for BICEP2/Keck Array (BK, shades of blue) and for LiteBIRD (LB, shades of red), in combination with the Planck 353-GHz dust template only (line contours) and the Planck dust and lensing B-mode templates (shaded contours). The lower panels show a zoom-in on the LiteBIRD contours.