Be careful out there.    This is a cautionary tale for both providers and clients.  If you travel outside the US and seek to re-enter you can be selected for "secondary inspection" by Customs and Border Patrol.  It doesn't matter if you are a US citizen or not.

Think of secondary inspections as a forced visit through your private life on a proctoscopic level.  They can demand all your electronic devices and associated passwords - and with them they can and WILL search through your life - emails, photos, accounts, browsing history anything is fair game.  You can be sitting in a small office somewhere for hours while they do this.   For US citizens it is an end-around on the constitution.  Yes you can refuse to give them the passwords and then they can deny you re-entry.

This doesn't happen that often but it DOES happen.

So heed the excellent advice form the prior post about browsing, TOR, and electronic safety.

Good luck and stay safe.  

They can annoy you and question you, but you do NOT have to let them search your phone or laptop.

Put a startup lock on it so that it requires a password when you first turn it on, then simply power it down until you are beyond their control...

I'm not a lawyer, but I know folks that work for CBP and here is what they have told me.
Being a US Citizen, you are right they cannot deny you re-entry; they can however detain you- the OP is correct on that point.

You are incorrect stating that ".. you do NOT have to let them search your phone or laptop."  and thereby insinuating you have a right or say in denying a search or prohibiting a border control agent from searching you and your belongings.
Laws cease to exist at border points, which is the point the OP made when stating to the effect the border searches are a way around US Constitutional rights and Laws.  That's the perception nowadays, but it has always been this way, its just the incidences of these searches has increased dramatically and there is no rhyme or reason why they search someone.  And people are getting swept up on charges because they forgot to delete or log out of an app from these searches.

So you can say "Nope, not opening my phone, not turning on my laptop, not giving you access to anything".  CBP will say " Very well sir, you are detained immediately, these officers will escort you to a holding room, and we will take your possessions".  They will keep you there however long they want, and they will still go through all your belongings.  If they cannot access your electronics, you might be released and told your free to go, but not your electronics- they will hold onto those.

The point the OP was making though- if you don't want to get caught with anything that can will cause judicial action against you- anonymize what you do, and make sure it doesn't walk around with you if it all possible.

END OF MESSAGE

yes, leostar is correct the cannot deny you reentry IF you are a US citizen but they can delay you and be quite a bother.  leostar is also correct make sure you have everything password protected at startup.