Because Trump told us so. During his speech on the Ellipse on J 6th Trump literally called on Pence to reject the certification of Biden's win and send the results back to the states? Soon after Pence issued a statement declaring he did not have the authority to do what Trump was asking him to do? Soon after this statement Trump fired up his angry mob claiming "this election was stolen from you, from me, from the country," and also falsely claimed the he won "in a landslide." Trump then went on to say "this is not the end, its just the begging" and stated the he "will never give up, we will never give up, we will never concede." Trump then urged his cult members to march on down to the Capitol Building claiming "if you don't fight like hell you're not going to have a country anymore".