sachar listening to a senior fellow at the hoover institution talking about the effects of covid-19 on democracies and authoritarian regimes. a big part of this strategy a lot of countries are using is what we might to be invasive surveillance of the location and the only one so that makes it seem accessible for the health challenge but you thought about wise that? >> yes. and those that were it with a different society it's an important problem and from the standpoint of human liberty. but the problem in part is that they have who has it been in contact with? then you can alert those people. it does is automate and speed up the contact tracer. on the other hand governments can use them to monitor for other reasons and what happens when we surrender our privacy our freedom from state surveillance and that we don't get that back after the crisis we cannot trust governments even very literate liberal governments to surrender these tools after the crisis is over first of all we should have a debate to what extent they want to surrender their freedom even now but in particular after the cr