Laptop Searches Legal?

At some point, the United States Customs and Border Patrol decided that the current administration's blatant disregard for the Constitution of the United States trickles down to them as well and implemented a policy of commonly searching the laptops of individuals entering the country even without any probable cause or legal justification. While this is not strictly related to air travel, my Top Ten Tips to Secure Laptops For Airline Travel seems appropriate- especially Tip #10. According to an article on NetworkWorld.com, two Senators are questioning this practice and suggesting that we should not throw the entire Constitution out just yet. Senator Feingold is quoted as saying "If you asked [U.S. residents] whether the government has a right to open their laptops, read their documents and e-mails, look at their photographs, and examine the Web sites they have visited, all without any suspicion of wrongdoing, I think those same Americans would say that the government has absolutely no right to do that." This is the land of the free, the home of the brave, yes? I served in the United States Air Force to uphold the United States Constitution and defend our way of life. Last I checked, the Constitution still has a 4th amendment that states "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized." Of course, we also have a 5th amendment that says "No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offense to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation." and we threw that one out after 9/11 under the guise of 'national security'.