They can indeed close their borders, as evidenced by the fact that they're doing so right now across the whole border with Slovenia (and they're far from the on

They can indeed close their borders, as evidenced by the fact that they're doing so right now across the whole border with Slovenia (and they're far from the only ones): https://home-affairs.ec.europa.eu/policies/schengen-borders-and-visa/schengen-area/temporary-reintroduction-border-control_en https://home-affairs.ec.europa.eu/policies/schengen-borders-... They can't do so permanently, but they can provide some sort of a justification every six months and keep it closed, nobody can veto them.