All across America, from Florida to Colorado and back again, the country‘s increasingly militarized local police forces are using a secretive technology to vacuum up cellphone data from entire neighborhoods – including from people inside their own homes – almost always without a warrant. This week, numerous investigations by major news agencies revealed the US government is now taking unbelievable measures to make sure you never find out about it. But a landmark court ruling for privacy could soon force the cops to stop, even as the Obama administration fights to keep its latest tool for mass surveillance a secret.