Cornyn is a good senator. But he’s not perfect. Specter is still important on issues coming up and we need his support. Cornyn is playing smart cards here; I imagine it’s distasteful to him too.
From Eisenhower to the younger Bush, the Republican Party has been ineffectual in reversing the growth of governmental power. If it is to be anything more than "Team B" of the Big Government party, it will have to reinvent itself. Both the outright RINOs and the compromisers will have to go. If not, even if Obama stumbles and he is succeeded by someone like Mitt Romney or Sarah Palin and a Republican Congress in 2012, his legacy and that of the Pelosi/Reid Congress will not be repealed. Then the next cycle that brings in the Democrats will continue the leftward push.
This dialectic has been going on since 1933. It must be broken. It will not be as long as liberals like Specter and compromisers like Cornyn are in charge of the alleged opposition party.