For the next few years, at least in cases that don't activate Justice Kennedy's libertarian streak, the interesting disagreements on the Court will be intra-conservative. Justice Alito's strong rejection of Justice Thomas's view in Morse v. Frederick is a nice example. Until some time in the 1980s, conservatives were generally unfriendly to free speech claims. Then, responding to what they saw as liberal/left "political correctness," most conservatives embraced freedom of speech as a value. Justice Thomas reveals himself here to be a throwback to an earlier kind of conservative.
To be sure, it's possible that Justice Thomas favors robust protection for free speech as a policy matter but fails to find it in the original understanding of the 14th Amendment. (Never mind his failure to pursue originalism when it comes to equal protection and even other free speech doctrines.) And it's also possible that Justice Thomas simply thinks schools are special, since he joins the Court's robust free speech decision in the campaign finance case. Still, Thomas is probably the least libertarian of the conservative Justices, which may make for interesting future disagreements.