For that you need to know how Europe looked like before WW I. Most countries you see in Europe now, weren't there. Such countries (nations) were in the four resident Empires of Europe: Ottoman. Czarist Russian, Austro-Hungarian & German (under the kingdom of Prussia) Empires. Plus the Netherlands, Belgium, Italy, Britain, France, Spain, Portugal have their extensive overseas Empires. This Imperial mix was inter-linked with all kinds of treaties, pacts, ententes (read SB Fay).
'Stability' you talk of, was ensured by these Empires. Politics then was all about how one Empire was engaging the others & Diplomacy (that idle pursuit that keeps rulers in the dark & complacent) reached its pinnacle.
Serbia threw off the yoke of Ottoman Empire a year before start of WW I and became independent. That part of (SE) Europe known as the Balkans was known as powder keg of Europe (powder here means gun powder). Gavril Princip, a nationalist Serb studying in Sarajevo, capital of Bosnia-Herzegovina, suspected to be a member of a secret Serb Irredentist outfit, shot dead the Archduke Franz Ferdinand, Crown Prince of Austro-Hungarian Empire & also his new bride. They were on a state visit to Sarajevo (Bosnia was in A-H Empire). the framework of treaties, pacts & entente swung into action. All Empires in Europe fell into their slots on either side of the battle lines. This spark, Princip's shot on June 28, 1914 prompting the aged Emperor of A-H Empire, Francis Joseph I to declare war on Serbia, supports all that I said above. Serbs claim that Princip was a liberal, up against an illiberal Empire.
If this is the state of European society, do you think there is place for 'liberalism'? Even if there was, it must not imperil Imperial norms of politics, society. Imperial forces that reshaped society by introducing a liberal dose of warfare (1914-18) that turned society upside down, challenged liberalism. It is not a war to be trifled with (for the sake of a liberalism argument), the centenary of which we are going to celebrate in two years. Its ramifications were felt for decades later, till after 25 years another much bigger conflagaration, WW II started its own history. Wars don't come cheap but are murderously expensive & for proof make your country (it is irrelevant which country it is) start a war to see how you as an individual will suffer. Europe pauperised by a war went into economic depression. The connected America that emerged as banker for Europe and as arms supplier getting sucked into the war, also suffered a much bigger (or rather a well-publicised & documented for historical content) depression.