This is temporary. They are registering as Republicans in order to Vote in the Republican Primary. They will then re-register as Dems.
Their priority is to knock out NEWT. That’s who they most fear.
They will support Romney or Santorum depending on which dynamic in a specific primary (meaning how the stealth Dems vote in South Carolina, may be different in how they vote in Florida)
Most likely they are leaning towards Santorum in an attempt to get rid of Newt (which won’t work, Newt isn’t leaving) and then think they can knock out Santorum, in order to get Romney to the convention.
Go Newt !!!! Don’t be fooled by these temporary Dem crossovers who are only in it to ensure the least Conservative candidate wins the Primary. They will lose in their attempt.