SPOILER ALERT!! Contains information and plot details upto the end of season 3 of Game of Thrones the TV show.
After yesterdays blog on Varys i thought I would stay in Kings Landing and focus on the Hand of the King Lord Tywin Lannister. I believe that even though he does not through blood have the right to the throne, through his skills have strategic management he would be the only one around who could actually rule the kingdom well. With the majority of people hoping for the fairytale of Robb Stark to charge down from the north and defeat the Lannister armies and become King of Westeros, yet unfortunately that dream was savaged destroyed through Tywins' scheming with the Freys and Roose Bolton. Whilst most will curse these three heads of houses I no doubt dislike the Freys and Boltons I applaud Tywin's strategic skill and cunning to literally chop the wolf's head off.
Skip back to the start of season 2 and with Joffrey now on the throne and the war with the Starks now in full throttle, Tywin now named as Hand of the King he takes charge of his forces and battles with King Robb. Even though he loses the first set of battles and is pushed back to Harrenhall he strategically manages to win the war. With Robb winning the battles he decides to take some of his forces and unite with the Tyrells army to save Kings Landing from King Stannis's forces, by doing this he concedes land to Robb whilst leaving some of his force with Kevan Lannister. This was crucial as losing the capital and the King would of destroyed the Lannisters and would of ended with the near annihilation of their family. From now at a base in Kings Landing he can avoid focusing on battles and now work out how to destroy the Stark threat. By linking up with the Freys who are disloyal and treacharous to their Liege Lord Tully he could of guaranteed his support to bring down the Starks. Whilst Roose Bolton was slightly more through luck as Bolton was only becoming disloyal to Robb through Robb's poor decision making with Jaime Lannister and Catelyn Stark.
Destroying the Stark rebellion and crushing Stannis at the battle of Blackwater Bay proves his management at being able to defend the Kingdom for many years to come from its' enemies. Whilst bringing his house from down in the gutters from his father to the ruling house of Westeros shows how prosperos and disciplined he is. With Joffrey on the throne and an heir in Tommen for now he has Hand of the King position secured and basically ruling the kingdom in all but name. Which is why it would be a great loss to the Kingdom if he was to become incapacitated in the upcoming series.