Oops.
According to a Michigan Republican State Committee (MRSC) member, Romney backers in statewide Republican leadership roles, including the governor and attorney general, pushed for an open Michigan primary. These open primary rules allow voters to vote in either party’s primary without declaring any party affiliation.
It turns out, Romney backers didn't just push an open primary in Michigan; they also beat back efforts to require signing a document affirming that voters were really Republican.
Governor Snyder’s staff whipped Republican statewide legislators into line on the open primary option. Michigan Attorney General Bill Schuette, Romney’s current state chair, joined the governor in whipping Republican elected officials into line on this. Michigan’s Lieutenant Governor Brian Calley, another prominent Romney supporter, joined in this concerted effort to achieve an open primary in 2012, communicating to every state committee member the governor’s position. Saul Anuzis, Republican national committee-man for Michigan and Romney supporter, also played a significant role in building support for the open primary.
Conservative Republicans opposed the open primary—sensibly. No primaries should be open. They feared that liberals would be able to meddle in the affair given the lack of a contest on the Democratic ballot. But Romney's team was convinced that they would benefit from liberal crossover support.
So now, while Romney moans about Democratic crossover voters, fact is, it was his team that made that crossover support possible. Ironic, isn't it?