Replication Data for: Western publics show strong yet constrained support for Ukraine’s defense against autocratic aggression

Russia’s invasion of Ukraine challenges the liberal international order and tests the capacity of Western democracies to maintain long-term military and financial aid for Ukraine in a foreign war. Understanding whether governments’ pledges of resolve are backed by their citizens is crucial for the credibility of these commitments. Here we show, based on survey experiments with 10,011 respondents in the United States, the United Kingdom, Germany, France, and Italy, that these countries' publics share a similar pattern of preferences. In all countries, citizens strongly endorse Ukraine’s sovereignty and self-determination while weighing human suffering and conflict escalation risk, but not economic costs. However, within countries, attitudes are polarized: roughly one quarter of citizens with pro-Western orientations show firm resolve, whereas another quarter with anti-Western views remain largely indifferent to political outcomes for Ukraine. These divisions indicate that democratic party competition could constrain the unity and durability of Western resolve against autocratic aggression.