If you represent a defendant and you want to strike a juror for cause because he or she is predisposed against your client, here's a quick and easy way to do it:
Q: Mr. Smith, you indicated on your questionnaire that you're familiar with this trial from the media coverage?
Q: Have you formed any opinions about my client's guilt or innocence?
A: Yes. I think he's probably guilty.
Q: But you told the judge that you could set aside your opinion and decide the case based only on the evidence, right?
Q: Does that mean that I would have to show you some evidence of innocence to change your mind?
By asking if the defense would have to show this potential juror evidence of innocence to change his mind, you are making a record that he does not presume the defendant to be innocent, but rather that the defendant starts from a position of guilt and the defense would have to prove otherwise to justify an acquittal.
Through this very simple exchange, and without embarrassing or angering the juror, you've just made your record to justify a challenge for cause.