For Rupert Murdoch, the three hours he'll spend in a small, "bland" committee room across from the House of Commons today, answering tough questions from MPs about phone-hacking and police-bribing within his company, is just about the most important three hours he's ever faced in his career.

On the line is very possibly the empire he's spent his entire adulthood building. In the past two weeks, the question being debated has gone from whether Murdoch's son, James, will remain his father's heir apparent, to whether Rupert will even be able to remain at the helm of News Corp. Board members are said to be unhappy with Murdoch's response to the crisis and are contemplating what was once unthinkable -- replacing him with his deputy, Chase Carey, if his performance today turns out to be disastrous -- as some board members fear it will.

The setting for Rupert couldn't be worse. Despite the fact that he controls a media empire, the tycoon has never been a very good public communicator. "He is awful at this sort of stuff," biographer Michael Wolff told the Guardian. "He is pretty inarticulate, mumbles all the time and is incredibly defensive."

He has never testified before parliament before and has only attended congressional hearings in the United States twice. There's a reason that so far the only interview he's given is to the Wall Street Journal -- his own paper (and even to them he raised a few eyebrows saying he was "tired.")

Murdoch has been preparing for the performance today like a candidate getting ready for a presidential debate. He's remained mostly behind closed doors for days rehearsing his answers with a team of advisors -- including lawyers and P.R. wizard Steven Rubenstein. But News Corp. executives who have watched Murdoch prepare are concerned about his ability to handle the tough questions, according to Bloomberg.

Murdoch will likely apologize again to the families of murder victims who had their phones hacked. But he is unlikely to accept criticism of his company's handling of the crisis, if the last week is any guide. He told the Wall Street Journal that News Corp. has handled the crisis "extremely well in every way possible" and only made "minor mistakes."

Also testifying today will be his son James and Rebekah Brooks, the former News International executive who was arrested over the weekend. Given the criminal cloud hanging over her, Brooks is unlikely to answer too many questions. Both James and Rupert will have lawyers sitting with them and may consult with them before answering questions.  

The parliamentarian chairing the committee hearing, Conservative MP John Whittingdale, has said he doesn't want the hearing to turn into a lynch mob.

But others on the committee have spoken of the need to ask aggressive or awkward questions. One person to keep an eye on is Labor MP Tom Watson, who is seen as a long-time critic of News International and the Murdochs (the Guardian called him Murdoch's "tormentor-in-chief"). He's solicited questions from constituents via Twitter. And he's likely to ask some very tough ones about alleged attempts to cover-up the scandal by James Murdoch -- who authorized paying millions of dollars to hacking victims over the years.

His stated goal: "To get Rupert Murdoch to apologize to the people his journalists have wronged."

Murdoch's goal now, it seems, is to survive.