The primary justification for school voucher programs in the United States has revolved around questions of efficacy, especially relative to student achievement outcomes. More recently, however, a series of studies revealed sizable negative impacts on students enrolled in voucher programs. Collectively, these studies presented an evidentiary sea-change and undercut voucher advocates' traditional claims regarding achievement impacts, presenting an opportunity for us to examine the strategies used to advance evidence on vouchers in new and traditional media. We identify several such strategies, including highlighting limitations of student achievement measures; explaining negative results through program particulars (e.g. overregulation or inadequate funding); demonizing opponents; and changing the conversation (e.g. switching to normative claims). We note voucher opponents' activities becoming more frequent and otherwise evolving -- e.g. becoming bolder and combining achievement results with other ideas and arguments to oppose voucher programs. Media coverage of voucher programs and research, more generally, fluctuated significantly according to broader political events. These findings reveal how research evidence can be leveraged in policy discussions and advocacy -- what we call 'strategic dissembling' -- whereby advocates and policymakers adjust in real time to changing empirical conditions as part of their long-term efforts to advance a particular policy agenda.