[W]hy don’t we send a memo to all drug traffickers, to all persons south of the border and in Imperial County and in California — why not our nation while we’re at it. Send a memo to them and say dear drug traffickers, when you hire someone to drive a load, tell them that they were forced to do it. Because even if they don’t say it at primary and secondary, they’ll get away with it if they just say their family was threatened. Because they don’t trust Mexican police, and they don’t think that the U.S. authorities can help them. Why don’t we do that?

What's wrong with those kind of comments? As the 9th Circuit says:

“[P]rosecutors may not urge jurors to convict a criminal defendant in order to protect community values, preserve civil order, or deter future lawbreaking. The evil lurking in such prosecutorial appeals is that the defendant will be convicted for reasons wholly irrelevant to his own guilt or innocence.”

...Similarly, prosecutors may not “point to a particular crisis in our society and ask the jury to make a statement” with their verdict...Nor can prosecutors comment on “the potential social ramifications of the jury’s reaching a...verdict.”

...Further, it is improper to make “statements designed to appeal to the passions, fears and vulnerabilities of the jury.”

The Court ruled:

The prosecutor’s “send a memo” statement urged the jury to convict “for reasons wholly irrelevant to [Sanchez’s] guilt or innocence.” The point of the “send a memo” statement was that if the jury acquitted Sanchez based on his duress defense