The big danger for the SLS will be when SpaceX's BFR starts flying. Not only will both stages be reusable, but for flights beyond the Earth a BFR will first go

The big danger for the SLS will be when SpaceX's BFR starts flying. Not only will both stages be reusable, but for flights beyond the Earth a BFR will first go into orbit, and next be refueled there by another BRF, and then take off with full tanks, instead of the almost empty ones as will be the case with SLS. The result is the BFR will be able to land 10+ times as much cargo on the Moon or Mars as the SLS, and at maybe 1 percent the cost per ton. I think what is going to happen is the tax payers will finally wake up to how they are being ripped off, and the SLS program will be canceled.