The challenge would be to destroy Conservative of all kinds (including Christian Democracy) and Reactionary parties permanently in elections in at least one European great power by 1900. Classical Liberals would replace them as the main right-wing faction.
IOTL, this happened in Denmark because the actual Conservative party killed itself. It also happened in France to a less extent, as Bonarpartists and Monarchists were utterly destroyed in early 20th century.
You can have 4 PODs: Post-Napoleon, 1850, 1868 and 1885.