After the invasions of Luxembourg and Belgium, Chancellor Bethmann Hollweg told the Reichstag that necessity knows no law. Germany paired that claim with its dismissal of the Treaty of London as a scrap of paper and its accusation that Britain was pursuing a national agenda. Every power was pursuing national interests, so Germany could not reasonably expect Britain to ignore a treaty and strategic concern older than the German state itself. Legal obligation and balance-of-power interest reinforced one another as explanations for British entry.
Notable Point · 1:42:38-1:47:13
"Necessity knows no law" and the Treaty of London
Germany justified violating Belgian neutrality as a military necessity, while Britain treated the same treaty as a durable strategic commitment.