I checked out 至上 and it says "supreme" as in supreme glory (至上光栄) and the other meanings are along those lines. It doesn't quite seem to fit the context.

I agree with Yumico, Richard and cinefil regarding "史上."

史上の on the other hand, means "historical."　It could be that this is a historical hearing for Jay Rockefeller (which I assume this is about.)




http://www.politico.com/news/stories/0310/33759.html
The Senate committee hearing, while carrying a far lower profile than last week's all-day House hearings with Toyota CEO Akio Toyoda, will be the first time that the administrator of NHTSA, David Strickland, testifies. Transportation Secretary Ray LaHood will also testify

http://www.reuters.com/article/idUSTRE6210JB20100303
Senate Commerce Committee Chairman John Rockefeller closed an all-day hearing into Toyota's safety problems by criticizing the testimony of three company executives and saying he believed mandatory brake override systems were required in addition to the floor mat and "sticky" pedal recalls.


http://findarticles.com/p/articles/mi_qn4188/is_20100207/ai_...
"The Toyota investigation is going to go down in history as one of the major probes of all times in auto safety, not because of the number of deaths, which are high enough, but because it captures the public attention," said Clarence Ditlow, executive director of the Center for Auto Safety, who has monitored almost every major automobile safety investigation in Washington for more than two decades. "You can't have vehicles that take off on their own."