jury selection is a very tedious process where every juror is interviewed by the judge and possibly both sides. They get whittled down by the court before being fully assigned, and then the prosecution and defense get to boot a certain number of jurors.

advising on jury selection is actually very lucrative business with both sides dishing out massive amounts of cash to make those checks.

in any case, in this situation, it’s not that they’re looking for unbiased jurors, it’s that they’re looking to balance out the biases of the individual jurors with jurors of apposing bias. I mean, you’d have to be living under a rock at this point to not have a bias as far as trump is concerned.