First, politicians will actually embrace the Common Core assessments and then will use them to set cut scores that suggest huge numbers of suburban schools are failing. Then, parents and community members who previously liked their schools are going to believe the assessment results rather than their own lying eyes. (In the case of NCLB, these same folks believed their eyes rather than the state tests, and questioned the validity of the latter--but the presumption is that things will be different this time.) Finally, newly convinced that their schools stink, parents and voters will embrace "reform." However, most of today's proffered remedies--including test-based teacher evaluation, efforts to move "effective" teachers to low-income schools, charter schooling, and school turnarounds--don't have a lot of fans in the suburbs or speak to the things that suburban parents are most concerned about.
I also wonder how the low performing southern states will react, although there is more variation within the between states, so maybe it won't be very noticeable.
I've been kind of amazed at how everyone just assumes the NECAP 11th grade math cut scores are just fine, even though it seems to be twice as hard to pass as the MCAS, so who knows.