The ACLU joined other legal activist groups to file a brief in what they call a potentially pivotal case in determining whether the government needs a warrant to track our mobile phones.
A statement put out by the Department of Homeland Security says that hunches and intuition are enough to justify warrantless searches, and it's not explaining anything much beyond that. It goes on to provide Constitutional analysis that's mostly redacted.
Last week, US counter-terrorism officials were granted permission to increase the period of time they can retain information about citizens, even if those citizens aren't tied to terrorism.
If you don't like the idea of the US government reading the sensitive contents of your computer, you may wish to take steps before you travel there.