From the fine people at Reason.com:

At the DNC. Rev. Al Sharpton, rushing from point A to point B, gets waylaid by a reason staffer. Another person horns in, and the following fragmented exchange occurs:

Fan: Reverend, Reverend! Can you sign my pocket Constitution?

Sharpton: (distracted) I won’t sign anything I haven’t read.

Sharpton rushes off, leaving a disappointed autograph seeker in his wake.