Conyers and Waxman, et al. are either threatening to issue subpoenas, issuing subpoenas, threatening contempt, yadda, yadda, yadda. 

What are the results?  Nothing, nada.  Current and former members of the Bush administration who receive these subpoenas use them for wall paper and keep thumbing their noses at Congress refusing to appear knowing there will be no consequences whatsoever for their actions.  Since members of Congress continue to impotently accept the cow pies of disrespect and insolence thrown at them by King George and his imperial court, why even go through these powerless, embarrasing exercises?

Karl Rove, who has been spilling his guts in the media, was a no show for a committee hearing citing executive privilege.  And he did so with impunity like Harriet Miers, etc.

No wonder Congress has a 9% low approval rating.  Its members deserve it.   All this nominal equal branch of government has been doing is sycophantically caving to or rubber stamping King George's demands.  They have brought the legislative branch of government to a new low by their lack of cojones, abrogation of their oaths of office, and arrogant disdain for the American people.