Why did Czech and Slovak leaders choose to form a single country in 1918?

In 1918, Czech and Slovak leaders chose to form a single country, Czechoslovakia, primarily to secure independence from the collapsing Austro-Hungarian Empire and to establish a sovereign nation-state based on the principles of democracy and self-determination.12

The union was driven by several key factors:

• Cultural and Ethnic Affinity: The two groups were closely related in terms of language, religion, and general culture, making a political union feasible.1
• Strategic Vision: Leaders such as Tomáš Masaryk, Edvard Beneš, and Milan Štefánik argued that divided nationalities should be allowed to form nation-states to act as allies of the West against German plans for European hegemony.2
• Allied Support: By organizing the Czechoslovak Legion and gaining international recognition from Allied powers, these leaders successfully positioned their movement as a legitimate successor to the Habsburg monarchy.2
• Political Necessity: With the Fourteen Points issued by U.S. President Woodrow Wilson advocating for the autonomous development of peoples, the creation of a unified state provided the best opportunity for Czechs and Slovaks to achieve lasting political autonomy.2