The Russian invasion of Ukraine has compelled Europe, including the Czech Republic, to reorient its security and defence posture towards the demands of high-intensity conflict. Since 2022, Prague has adopted new strategic documents, increased defence spending to 2 per cent of GDP, launched substantial procurement programmes, and assumed a leadership role in allied support for Ukraine, most notably through the international ammunition initiative. Nonetheless, Czech defence policy continues to grapple with significant challenges: political polarisation over military investments, limited public support for higher defence expenditure, persistent recruitment difficulties, and enduring infrastructure and interoperability shortfalls. NATO’s recent commitment to raise spending to 5 per cent of GDP by 2035 amplifies these pressures, requiring structural reform and more extensive societal engagement. The Czech case highlights both the potential and the vulnerability of small states within European security: capable of exercising leadership through targeted initiatives, yet constrained by domestic political, social, and fiscal factors that threaten to erode long-term strategic ambition.