I'll Debate Any Time, Any Place...Except

Not. [Link]

John McCain has accepted an invitation to appear at a nationally-televised town hall meeting next month organized by a coalition of support organizations. Despite pleas from the group, Barack Obama has refused to appear at the same event, underscoring his desire to avoid extemporaneous exchanges with John McCain, especially on military matters in which he has no experience at all. The Fort Hood group has offered to change dates, but Obama remains obstinate:

But earlier in the campaign

On several occasions, Obama challenged McCain to debate foreign policy and the war, “anywhere, any time”.

I wonder why?