The Drunk

A police officer pulls over this guy who's been weaving in and out of the
lanes. He goes up to the guy's window and says, ... Sir, I need you to
blow into this breathalyser tube. The man says, ... Sorry, officer, I
can't do that. I am an asthmatic. If I do that, I'll have a really bad
asthma attack. ... Okay, fine. I need you to come down to the station to
give a blood sample. ... I can't do that either. I am a hemophiliac. If I
do that, I'll bleed to death. 
... Well, then, we need a urine sample. 
... I'm sorry, officer, I can't do that either. I am also a diabetic.

    If I do that, I'll get really low blood sugar. 
... All right, then I need you to come out here and walk this 
    white line. 
... I can't do that, officer. 
... Why not? 
... Because I'm drunk.