Border control at the external borders is in the interest not only of the Member State at whose external borders it is carried out, but also of all Member States which have abolished internal border controls.
Ní hamháin go dtéann rialú teorann ag na teorainneacha seachtracha chun leasa an Bhallstáit a ndéantar ag a theorainneacha seachtracha é, ach téann sé chun leasa na mBallstát go léir a bhfuil deireadh curtha acu le rialuithe ag teorainneacha inmheánacha.