The best line of attack on Sotomayer is the 2nd Amendment. From what I have read, she basically thinks guns are a Fed only issue thus the states are free to impose whatever regulations they want including outright bans.
Like most liberals (and some conservatives) she advocates the silly idea that states rights apply to some Amendments, but other amendments should be federally imposed.
The gotcha for Sotomayor is that after Heller we all have rights to own guns ...in D.C.
Heller has not been incorporated. An incorporation lawsuit is in the works and heading to the SCOTUS. Republicans can pressure red state Dems on this issue because she supports local and state bans. Interesting enough Montana is challenging Fed gun laws using the same point but attacking the commerce clause. If the states can make their own gun laws then Fed regulations are moot ... IL can ban all guns and MT can sell machine guns with no restrictions. (Which would irk gun-ban Libs to no end).
So she puts Dems who support her in a no-win situation on this issue.
Republicans should make the most of it. Sotomayer will probably get confirmed, but not without a heap of Dems getting hammered for it in the next election for supporting a gun-banning jurist or a machine gun-allowing jurist (depending how you look at it). Chances are the incorporation case will come up and be decided before the next election for many of the new senators.
Obama & Co. thought they had the GOP in a corner on this nomination. Combine this with her racist comments and the Ricci v. Destefano decision. This might blow up in their faces. 27 Senate rats voted for concealed carry rights in national parks.