Is ethics necessary in the government? Why??

If you can't figure this out on the basis of simple common sense, then you're in deep trouble.

Yes.
Should be obvious.

Law is ethics codified (made in to law). No law is created that does not contain the ethics that make that law work.

Next, ethics must be highest priority when implementing laws. Take the case of the IRS and the woman who held up the applications of the Tea Party groups. She was not ethical.

Apparently not, which is why we're in such a mess.