Reasons state legislators gave for opposing the Common Core used to be pretty predictable. They worried the standards cost too much, were imposed without their consent, or impinged on local control.
Since 2012, though, the reasons state lawmakers don't like Common Core have exploded, as reflected in the bills they've introduced that oppose the standards:
All this happened as the Common Core was getting more legislative attention, period. State legislatures have considered 785 Common Core bills between 2011 and 2014, according to a forthcoming research paper in Publius summarized by the Brookings Institution's Governance Studies program. About 30 percent of those bills were negative — trying to drop the standards, prevent their implementation, or simply express disapproval. (The majority of state legislature bills about the Common Core were in support of the standards — a surprising finding in itself.)
Some of these are probably the same basic objection in different clothes. You can classify it as "parent engagement," "local control," or "oversight," but the general idea is the same: that Common Core takes decision-making about education away from where it should be.
Some of the other new objections show that all the big education debates are getting refracted through the Common Core lens.
Standardized testing was in place long before the Common Core — the standards just change which tests students take — but the tests have now become the focus of a backlash among suburban parents. As the education technology sector booms, concerns about students' data being used by corporations and other third parties are growing. That's not directly linked to Common Core, either, but those apps are often used to teach lessons aimed at meeting the standards.
As the paper's authors, Ashley Jochim and Lesley Lavery, write, this is why getting Common Core implementation right is key. Other controversies, such as whether teachers should be evaluated based on their students' test scores, end up influencing perception of the Common Core itself — regardless of whether they have anything to do with the standards.