Why worry unless you are a terrorist?
Because these laws allow action based on suspicion. Now, fair enough, this doesn't let you bang up just anybody, but it's still very lucrative.
Plus the 28-Day limit is already the highest in the Democratic world.
These comparisons from last week's Economist are very interesting:
Australia has 12 days, Turkey and Ireland have 7, France has 6, Spain and Russia have 5, Italy has 4, Germany, New Zealand and the USA have 2, and Canada has one.
Spain for instance has a greater terrorist problem than we do, so why do we need over 7 times more then them?
42 Days won't make the situation much worse, but it's completely unjustified overkill.