Leahy appears to believe that the fact that Bush has (reportedly) cited the theory of the unitary executive in 103 signing statements refutes Alito’s contention that there is no connection between the theory and the statements. It doesn’t. Alito means that support for the making of signing statements does not imply support for the theory (or vice-versa)–they’re different topics. You can support the making of signing statements without accepting the content of any particular statement. Similarly, the fact that Leahy brings up both concepts in the same sentence does not prove that they are “connected” conceptually.