 Post censorship was retained during the interwar period and afterwards, but without being done on such a massive scale.The opening of international mail outgoing and incoming from the United States by US Customs under the Trade Act of 2002 occurs under the border search exception to the Fourth Amendment.This practice has had some criticism (including allegations that it adds to the expense of conducting the Postal Service and can thus affect postage rates), of which the USPS apparently informed Congress before passage of the legislation.