▁January ▁ 1 , ▁ 1 8 0 8 , ▁the ▁first ▁day ▁it ▁was ▁permitted ▁to ▁do ▁so , ▁Congress ▁approved ▁legisl ation ▁prohib iting ▁the ▁import ation ▁of ▁slaves ▁into ▁the ▁country . ▁On ▁February ▁ 3 , ▁ 1 9 1 3 , ▁with ▁rat ification ▁of ▁the ▁Six teenth ▁Am end ment , ▁Congress ▁gained ▁the ▁authority ▁to ▁le vy ▁an ▁income ▁tax ▁without ▁app ort ion ing ▁it ▁among ▁the ▁states ▁or ▁bas ing ▁it ▁on ▁the ▁United ▁States ▁Census . ▁The ▁third ▁text ually ▁ent rench ed ▁provision ▁is ▁Article ▁One , ▁Section ▁ 3 , ▁Cla uses ▁ 1 , ▁which ▁provides ▁for ▁equal ▁representation ▁of ▁the ▁states ▁in ▁the ▁Senate . ▁The ▁shield ▁protect ing ▁this ▁clause ▁from ▁the ▁am end ment ▁process ▁is ▁less ▁absolute   – ▁" no ▁state , ▁without ▁its ▁consent , ▁shall ▁be ▁dep riv ed ▁of ▁its ▁equal ▁Su ff rage ▁in ▁the ▁Senate "   – ▁but ▁permanent . ▁ ▁Article ▁Six ▁Article ▁Six ▁establish es ▁the ▁Constitution , ▁and ▁all ▁federal ▁laws ▁and ▁treat ies ▁of ▁the ▁United ▁States ▁made ▁according ▁to ▁it , ▁to ▁be ▁the ▁supre me ▁law ▁of ▁the ▁land , ▁and ▁that ▁" the ▁jud ges ▁in ▁every ▁state ▁shall ▁be ▁bound ▁thereby , ▁any ▁thing ▁in ▁the ▁laws ▁or ▁constitution s ▁of ▁any ▁state ▁not with standing ." ▁It ▁valid ates ▁national ▁deb t ▁created ▁under ▁the ▁Articles ▁of ▁Confeder ation ▁and ▁requires ▁that ▁all ▁federal ▁and ▁state ▁legisl ators , ▁officers