If somebody invented smart glasses that detected lying, how do you think the public would react?

I would start being overly honest and forthcoming about things I don't currently bring up because doing so isn't polite. Wouldn't want to lie by omission!

True, if it's designed to detect deceit it won't detect self-delusion.

It would destroy civilization instantly, since it relies on lies all the way down.

People would very, very quickly start to rationalize why the detection couldn't possibly be right. Look at how many scientifically or historically proven things people already are willing to disregard because it conflicts with their worldview or beliefs!

So they detect "willful" deception? People would just fall back on the "...well, I didn't know" / "didn't think XYZ counted" / "didn't consider ABC" as their excuses. Or if it can be shown that 0.00-near-infinite-zeros-01% of the population has some quirk which makes them detect wrongly, suddenly there'd be most of the population claiming that.

Lawyers would be fucked.

To sum that up, are you saying people would find reasons to disbelieve that their heroes and icons are lying? I was thinking more along the lines of personal contact - everyday conversations, business deals, etc.

Yep. Their heroes, icons, leaders, family... and themselves.

Hell, they'd disbelieve if the glasses detected someone was telling the truth, but they didn't want to believe that!

It’s devastating to my case!

But we already know politicians are lying and they still win elections,

I read a book around 10 years ago that convinced me that lying is almost never justifiable even when it comes to white lies and I've pretty much not ever lied since. And I'm not talking about radical honesty - not lying means not saying things that you know to be untrue, not that I always tell everything that's on my mind.

Few observations that have came from this experiment:
- Most people lie constantly in situations that they wouldn't need to and they don't even realize it.
- The cartoon examples people think of about situations where you're forced to tell an uncomfortable truth almost never happen.
- People can't wait to brag about how good of an liar they are when the lie has been directed at a 3rd person - not realizing that gets them immediately labled as untrustworhy in my eyes.
- Not lying to others also makes it more difficult to lie to yourself and forces you to face your bullshit
- Most people absolutely hate for anyone to even suggest taking lying away from their toolkit (see this thread)

Politics would make them illegal so fast, your head would spin.

Without lies any civilization would collapse in a matter of minutes: faced with what all of us really think, most people would kill one another (or commit suicide) even faster than that, as all the wishful-thinking and illusions so many of us rely upon would instantly vanish.
People would try to get rid of that tech (and in the process some would decide to do some nasty things to their creators/advocates) trying to save themselves from that very short lived hell this tech created. And they would fail.

object on privacy grounds

That would be the reasonable thing to do.

I agree with these points, but you should talk to the other person here who said without lies civilization would collapse in a couple minutes. Quite the spectrum of beliefs.

I read a book

share?

I strive for honestly in almost all things. I have a few relationships where honesty doesn't really work unless I want them to become very stressed out - innocuous inquiries like 'how are things?' <surveys the hellscape of our national politics/ society / ai etc.> they're dealing with dementia already, I can't be honest in these kinds of interactions.