Nationalism affects foreign policy decisions by prioritizing national interests, identity, and values over global concerns. Nationalist sentiments can steer countries towards more unilateral actions, emphasizing sovereignty and often leading to resistance against international agreements that might be seen as compromising national identity or autonomy. Such policies may result in tensions with other nations, as nationalist governments may favor strict immigration controls, trade protections, or military interventions. Conversely, nationalism can also drive a nation to engage more robustly on the global stage to project power and influence.