"Some people abuse the welfare system."
Dog whistle!
"Opposing Medicaid expansion could cost lives."
Dog whistle!
Also, use the term "_________[Republican/Democrat/extremist] talking point" to the same extent. It works really well in winning group-think arguments.
"People abuse the welfare system" isn't a dog whistle. "Welfare queens" is the definition of a dog whistle.
And so is putting up a picture of a scary-looking Black man named Willie Horton with the captions "RAPING," "STABBING," and "DUKAKIS ON CRIME."