can be useful in buying time if they are done the right way and to be sure they are a blunt instrument. they have significant economic consequences. they draw a lot of consternation from other countries, so if you're going to go all that way and do travel restrictions, you might as well do them right, so, first is we're allowing american citizens and permanent residents from soften africa to return wits right thing to do, but we should at least require for them to go into quarantine and then get retested especially because we know in hong coming, for example, there are people in quarantine facilities who are testing positive. in addition, we now know that there might be even be community transmission in other countries like the uk and if we're going to do this, let's do it the right way. i'm not saying across the board ban all travel but why not ask all returning international travelers to at least self-quarantine and then get re-tested in five days. >> dr. wen, you also suggest the president, and i'm putting up as i do this the map of the cdc transmission in the united states right now. you also suggest that the president should be more