Can a defendant succeed on a claim of ineffective assistance of counsel based specifically on counsel's failure to move for severance?

For a defendant to prevail on a claim of ineffective assistance of counsel based specifically on counsel's failure to move for severance, "he must show that reasonably competent counsel would have moved for severance, that such motion would have been successful, and that had the counts been severed an outcome more favorable to him was reasonably probable." (People v. Grant (1988) 45 Cal.3d 829, 864-865.) Defendant cannot demonstrate that a motion to sever would have been successful. "Counsel's failure to make a futile or unmeritorious motion or request is not ineffective assistance." (People v. Szadziewicz (2008) 161 Cal.App.4th 823, 836.) Accordingly, he cannot establish ineffective assistance of counsel in failing to move for severance.

The phrase "connected together in their commission" as used in Penal Code section 954