How have the courts treated defense counsel's errors?

Finally, defendant argues that defense counsel's acts and omissions cumulatively resulted in prejudice. However, at most, we have found harmless error in counsel's failure to investigate the new video footage that was discovered during trial, and the court's exclusion of defense investigator's testimony on "Shottas." These minor errors did not cumulatively amount to reversible and prejudicial error, or result in a violation of due process. (People v. Leonard (2007) 40 Cal.4th 1370, 1414-1415.)