Is it right to wage war to export democracy, or - as Kant would have said - to forcibly interfere in the constitution and in the government of another state with the goal of transforming it into a republic? The answer of Kant, contained in the fifth preliminary article of the Perpetual Peace, leans towards non-interventionism: a bad constitution can never justify a war, because it may be the root only of a scandalum acceptum. To understand the meaning of scandalum acceptum we have to become aware that it is a term originating from moral theology, which we should translate into the language of international law. The scandal, as it was still clear to Kant’s contemporaries, is the sin of advertising a sinful behavior: but it is just a scandalum acceptum if the act that inspired others to sin has been done without the intention to give them a bad example. A flawed constitution can be only the occasion of a scandalum acceptum because its legal power does not spread its influence beyond the border of its state. If a nation chooses to imitate the allegedly wrong constitution of another state, its choice depends only on its sovereignty, because it is a matter of internal constitutional law. On the other hand, waging war against another country because of its allegedly flawed constitution is a worse kind of scandal, the scandalum datum, because it involves an international law principle of limited sovereignty according to which every state has the right to assault another state because of its constitution.