The inability to meet impossible standards is not a license for demagoguery.In fact, US President Barack Obama can blame himself for some of the pressure he feels over the Gulf of Mexico oil spill.He took office promising the impossible across a broad spectrum of national concerns. Now, critics from both major political parties demand to know why he hasn't snuffed the Macondo blowout.Well, he can't. It's not in his power or that of any other official of government to kill that well.BP must do the job. BP knows the reservoir and the well history. It has expertise the government lacks.Obama and others in government have strong roles to play. In the end, however, BP will kill the well. Expec...