Calling someone "anti-Semitic" if they criticize the govenment of Israel, or calling someone "unpatriotic" or "un-American" if they criticize the Bush Administration is an example of the argumentum ad hominem--which is to say, an attempt to draw attention away from an assertion by attacking the person who makes the assertion.   It, in no way, refutes the assertion itself. This is a diversionary tactic and should be met with the contempt it deserves.

Don Firth