What is the legal (Sharia) position regarding a marriage contracted for the purpose of obtaining citizenship, after which the wife disappeared? Is the contract considered void due to the absence of a guardian (wali) or the lack of intention? Is the wife still considered to be under his marital authority (in his 'ismah)? And how can she be divorced despite her whereabouts being unknown?

A sham marriage, contracted to obtain official documents, is forbidden by Islamic law because it does not intend the reality of a legitimate marriage, nor is the will directed towards it. The contract thereby deviates from its Sharia (definition) objectives and includes conditions that contradict its purpose. Its ruling in court depends on proving its sham nature; if proven, the court will rule it invalid. If not proven, it will be ruled valid if its pillars are fulfilled and its impediments are absent. If your marriage was a sham and did not meet the conditions for validity, it is void and does not require a divorce. However, if the conditions were met and there were no impediments, then it is a valid marriage. If the condition of the guardian was absent, then the marriage requires a divorce or annulment.