One view states that governments are expected to have access to phone call data of the population, so that safety can be maintained. In contrast, another view says that those data are private, and governments must have consent to access them. While both views have their own merits, I posit that those data must be private by default for the best interests of all parties.
One opinion says that governments should be able to access phone call records and messages to avoid risks which potentially undermines national safety, such as terrorist networks. In the early 2000, many countries in the middle east were experiencing many political and military conflicts, in which many groups tried to topple the legitimate national institutions by creating a myriad of chaos. In that scenario, it is very plausible for a nation to impose surveillance on phones, so that those groups can be easily identified and national safety can be restored, despite compromising privacy at certain degree.
As countries become more stable in the current years, there is much fewer to worry about in terms of their security. In fact, exposing smartphone call history and texts to regimes in power may become a threat to population in various spheres, such as politics and business. The regime with ill-itention may use the data they receive to make an informed decision to black-mail other political opponents, so that their presidential candidates could win in elections. Or they could collaborate with enterprises to crush their business rival. Various studies in many countries have shown that the vast majority of people disapprove their national institutions to gain access to their private phones data because of the same reasons.
In conclusion, while governments accessibility to phone call data could be very beneficial in a time of conflict, I posit that the phone data must be private by default, because the same accessibility could be abused by the governments for their own interests.