As a discussion of John McCain goes on, the probability tends to one that a die-hard McCainiac will, in response to an attack on his guy, change the subject bringing up Mitt Romney.
As a discussion of Mitt Romney goes on, the probability tends to one that a die-hard Mittster will, in response to an attack on his guy, change the subject bringing up John McCain.
In both cases, it’s a sign that the die-hard fan has probably lost the argument.