Employees refuse to provide Social Security number - what can we do?

What are my options if a new employee refuses to provide their social security number on a W-4? I have had employees write in "invasion of privacy."

Rita Risser replies:

Your only option is to explain to them that if they don't provide it, you will terminate their employment. By law, you are required to have this information for tax purposes. Failing to obtain it could mean that you are guilty of tax fraud.