Why should he? Clinton didn't.
he should quit not just because the Democrats are running worse criminals, but because there is no evidence he has committed any crime.
There is no crime to free speech stating US law,
Thousands of Spanish speaking foreign born registered voters were reminded in a letter that it is against the law to vote if they resided here illegally .
This district (including Santa Ana CA) has a very high probably of a person speaking Spanish they are more than likely illegal, AND if they are registered to vote that does not clear them from being suspect as being an illegal immigrant because This district has a history of illegal being registered to vote in the past, and local media has boasted that they were registering illegal immigrants to vote in this particular elections by the thousands
So bottom line there was no crime committed by the person who sent these letters out as a realistic reaction to what is happening in this district regrading the flaunting of US law.
Furthermore Tann claims a supporter of his sent the letters without any knowledge and that one word may have not been translated properly by the press regarding immigrant, which really in context the warning was directed to illegal immigrants, so even if he did authorize these letters, they speak the truth, it is a US Federal crime to fill out a voter registration Nada vote if a person is not a citizen of the US and there has been no crime committed.
so no he should not quit...