DanP said:
"Liberty is a wonderful thing, as long as it doesn't become the liberty of another being to enter in your home, kill your child, rape your wife and make you watch all this."
I guess it depends on how you interpret that phrase.
Does a person have a right to enter your home, kill your child and rape your wife without the fear that you'll shoot him? No, of course not. You have a right to prevent someone from entering your home, killing your child, and raping your wife.
Should it be possible for a person to enter your home, kill your child, and rape your wife? Yes, it should. For one thing, thinking you could make it impossible is unrealistic - you can just reduce the risk. Secondly, liberty is worth it.
Obviously, the idea that the quality of life difference between a riskier liberty and a safer lack of liberty isn't a unanimous opinion. In fact, people in a country become very willing to give up more and more liberty as the chances of dying violently increase.
For a Tsutsi in Rwanda, or for a Jew in Germany during and immediately prior to WWII, trading liberty for safety could be seen as a very good trade. For an American, where 1 out of every 100,000 is killed by airplanes flying into buildings, the trade off isn't quite so clear cut.
With a risk twice as great as being struck by asteroid, many Americans would give willingly give up liberty if the risk of dying in a terrorist attack would be reduced to what? Half as great as being struck by asteroid, a fourth as great? The questions about how much the risk has been or will be reduced have never really been answered. There was just the promise that actions that seemed somewhat unconstitutional would reduce the threat of terrorist attack - by some undefined amount.
With a risk of 100,000 to 1 for each terrorist attack, many Americans would also be unwilling to give up liberty even if there were a terrorist attack every year. At that rate, the chances of dying in a terrorist attack would be about 1300 to 1 - still 15 times less likely than dying in a car crash. Many Americans would find it absurd to give up liberty for such a small risk.
In fact, for a short period of time (less than 5 years), America could probably handle a WTC attack once a month before I would even consider reducing liberty to combat the threat. That would be about equal to the rate that Americans died in WWII. It would be less than civilian casualty rate of Great Britain in WWII, mostly due to German bombing (about 1 of every 713 British civilians died because of the war), and that casualty rate just strengthened British resolve.
I guess the idea of liberty and risk need to be quantified, since there are situations where DanP's comments would be very true - I'm just not sure there are very many.