You can make use of these bumper stickers:

The reason for these particular messages should be pretty obvious to
 any thinking person who has been closely monitoring recent events.

This is a subtle way of letting others know that you're concerned about 
the creeping tide of irrationality which seems to be engulfing our country. 

To get these stickers, print this file and this file onto white full sheet 
labels ( obtainable from any office supplies store ), and then 
do a simple cut-(peel)-and-paste of the old-fashioned kind. 

If you don't have a color printer, a copy center can probably
do the job for you. Save the files onto a floppy disk and hand
 the floppy to the copy center operator.