Why Are Sanctuary Cities Necessary

Josephine,
I respect your opinion that sanctuary cities are unconstitutional and I agree with you, but I do not agree with your reasoning as to why. After reading your stance on sanctuary cities, I have to admit that I am confused by your explanation of them. First, you imply that being an undocumented immigrant is a crime, when in fact it is only a civil violation. What is illegal, and actually classified as a crime, is the improper entry. An example of this is illegal border crossing.
Furthermore, you seem to imply that if an immigrant in a sanctuary city were to commit a crime, they would not be charged for the crime when in fact, they will be charged in the same manner as if they were an American citizen. The only difference is that