Alito doesn't have quite the track record on federalism of Michael Luttig, the other name that was in the rumor mill. But Alito played a role on the right side of Planned Parenthood v. Casey, and as Ramesh Ponnuru pointed out in his chapter of A Year at the Supreme Court,
The legal conservatives who have cheered the Rehnquist Court's supposed federalism tend to put cases such as Casey in a different mental category from the federalism cases. But this is a mistake. Restrictions on moral federalism remove the political basis for any contemplated federalist "revolution." The reason for this is that moral federalism is the only kind of federalism that might have some robustness.Expect to hear a lot more about Casey.