Abstract This paper analyzes the morphosyntactic variation in past counterfactuals with modal verbs in Pomerano, a Low German variety spoken in Brazil. The variation concerns (i) the highest verb (temporal auxiliary or modal verb), (ii) the morphological form of the temporal auxiliary (blocking of tense and/or person agreement), (iii) the frequently unexpected position of the modal verb (verb clusters in the CP-domain), and (iv) the overall number of verbs (syntactic doubling and/or PF-insertion). Analyzing more than 6,000 translated sentences, scope rivalry between the temporal auxiliary and the modal verb proves to be the major catalyst of an intriguing instance of language variation and change. The derivation of the extant variants grants us a privileged view of the clausal architecture of Pomerano—including cases of derivational misfiring—as well as of more general processes of clause formation.