Encryption backdoors, breaking WhatsApp and iMessage's security to let the government stop Bad Things, sounds like a reasonable idea. The British government secured the powers to do this and, although they have not yet persued this, there is a constant push for the government to force messaging apps to create these backdoors.
To those of us who remember a world before smartphones and the internet, it really does sound reasonable. After all, it has been possible to wiretap suspects for decades and comprehensive checks and balances have been developed to stop the abuse of that power. Tom Scott explains why, when you look at the details, it isn't a good idea.