Is a husband entitled to interfere in his wife's political choices, and is he responsible for her by virtue of the Hadith, "All of you are guardians and responsible for your subjects," or is it a matter of personal freedom for the wife?

Permissible jurisprudential disagreement is not a matter for denouncement. If the disagreement between a husband and wife falls within this type of issue, the husband should not compel his wife to adopt his choice, unless her own choice would lead to harm. If the wife believes something to be forbidden or obligatory, she is not permitted to obey her husband in committing the forbidden or abandoning the obligatory. As for permissible matters, she must obey him unless it causes harm. Political issues are often based on ijtihad (independent reasoning), and should not be a cause of disagreement between spouses. However, if the matter relates to an obligation or a prohibition, the situation is different.