At the macroscopic level,the mere simultaneity of medium to high levels of legitimacy and significant but contained institutional change weighs in favor of the notion that the party’s program of institutional change has successfully responded to public preferences.
在宏观水平上,仅仅是合法性从中等到高级水平,以及包含制度上的变化的象征——这种象征支持了政党制度上的改变——就已经成功的回应了大众的喜好.
你给的好像不全,我找了一下原文,偶不是学政治的.所以只能翻成这样了.