The US lawyer for Edward Snowden has questioned whether the law to retain metadata can improve national security, after Australia introduced the bill to parliament.

Snowden’s lawyer said there was no good evidence that data retention could help national security authorities to prevent terror attacks. He acknowledges that the retention of metadata could help connect the dots after the attack already took place, but pointed at the lack of evidence that mass surveillance can prevent terrorist attacks.

The Australian government introduced the bill that would force phone companies and ISPs to retain users’ metadata (which is a digital footprint left behind when people use their devices) for 2 years. That data would be available to law enforcement agencies.

The country’s communications minister said that the law would not increase the extent to which metadata could be obtained by the authorities. He explained that the bill would rather establish an industry-wide standard to make sure telecommunications companies kept this information for 2 years.

However, both the prime minister and the chief architect of the data retention bill failed to clearly explain what data would and would not be collected under the proposed law when they first floated it. For example, it was claimed at the time that web browsing history wouldn’t be included in data collected. As a result, the tech experts and civil libertarians had to call on the government to release an exposure draft of the legislation, which would clearly define metadata and explain exactly what oversight provisions are expected to minimize the potential for data breaches.

At the same time, it is unclear who would bear the costs of the retention program, but as usual the guesses are that they would be handed down to consumers in the form of a “spied upon tax”.

The Australian government argued that data retention is necessary to protect citizens from terrorist cells and lone wolf attacks. However, public sentiment turned against data retention back in 2013, when a whistleblower Edward Snowden disclosed the extent to which American NSA was monitoring and storing phone and web data.

Although Snowden’s lawyer himself is against data retention, he had to admit that the Australian government has handled the issue well, pointing out that it managed to avoid the veil of secrecy that is normally “deeply corrosive” to public trust.