When ISPs delete data, child pornographers can't be found

And think of all the murderers who can't be caught because the walls of private homes absorb the sound waves rather than recording them and sending them to the government.

But seriously, governments are supposed to enforce laws to preserve the rights of people to be free, not strip away the rights to enforce the laws. People's freedom is primal, privacy is an important part of freedom (it means you can do lawful activities without fear of repercussions, either from governments abusing their power, or criminal groups which have used the same systems), and so violating people's privacy to increase crime detection rates is a bit like rigging your house with dynamite to stop vandals.

Even if you trust your government and ISP employees, strong physical and computer security is hard, ISP data retention systems are complex, and if the data is retained, sufficiently motivated criminal groups can get access to it easily.

"further opportunities to innovate around the preservation model"

That needs more buzzwords, like 'synergistic' or 'proactive'.

Seriously now, surveillance is not merely a tool to catch criminals, it's a new power governments are getting. This power can be used to fight child porn, but also spy on political opponents. The individual is also losing avenues of recourse in the case of wrongful (or malicious) convictions. Electronic evidence can be tampered with much more easily.

Governments again failing to understand the technology they are regulating. Catching the foolish criminals only works a few times, they get smarter and hiding your tracks on the internet is fairly easy if you've got a good reason to do it.

The criminals will disappear in a puff of smoke and all that will be left in the mass invasion of privacy of the average person.

I think another example is required:

A ['Cracker breaks in', 'employee goes rouge', 'a police officer abuses power', ...] and steals all the ['users internet history', 'SMSs', ...] on the system. Which is preferable:

A) Since most of the data has been properly deleted, the thief only has access to the last few days of data to sell or do what they want with.

or

B) Since the government has made it law for the data to be keeped, the thief has the last 6 months to 2 years worth of data to sell or do what they want with.

Which of these do you think will help children get raped?

And I am not even starting on privacy invasion by the government...

oh yes. bring the "safety of kids" argument for tracking every click of mine. No thanks.