On this issue (post 9/11 security) I would seriously doubt the 35% figure and would, at the very least, double your figure. On most political issues in general I would tend to believe that a 51% figure is a little too, uh... conservative. I think there is a vast silent majority outside the Beltway and throughout flyover country that the MSM and political punditry ignore. These were the people that enabled George Bush to win two elections despite an allout assault from the MSM.
In point of fact the first election did not show Bush with a majority of the popular vote. And a small majority of the popular vote in the second is not indicative of any vast majority on the scale you postulate.
Polls indicate that around 35% consider themselves conservative and about 25% liberal. Bush was able to attract a lot of moderates concerned about National Security during his campaigns.
Since a large percentage of eligible voters did not do so I would assume these are neither conservative nor liberal. This group is larger than either the conservative or liberal groups. I will call this the Meathead Majority though it is actually a plurality.