NPR interviewed Michelle Rhee, CEO  of StudentsFirst and former Chancellor of D.C. Public Schools. Here’s a bit of  the Q and A on post-Vergara court challenges to current teacher tenure laws:

Besides New York and California, which states do you think are ripe for a challenge?
There are probably conversations going on in four to five states right now, thinking about this and trying to figure out if it’s relevant for their state whether there’s a litigation strategy. That’s our sense of it, being on the ground. Some states across the country have begun to make changes at the district level or legislatively, but in many states, the litigation strategy and going through the courts is a different way to [make the changes]. 

Minnesota, Connecticut, New Jersey and New York are on that list?
Yes they are. There’s talk in Tennessee as well. 

Union leaders say they’re not opposed to shortening the time it takes to fire a bad teacher or lengthening the time it takes to get tenure, but they say that these policies are not hurting kids. Other factors are to blame, like poverty, broken homes, inadequate school funding.
The unions are absolutely right. There are other issues that go into why our nation’s schools are not performing well. There are many other factors. Vergara did not say [tenure/seniority] were the only factors and, therefore, if we fix it we will solve the problem. The judge simply said there are currently laws and policies in place that, if you look at the data, clearly these laws disproportionately impact poor, minority kids negatively, and we should fix or remove those policies.