This is ridiculous- day trips to Mexico will require a passport or proof of citizenship?
Not that I like any parts of Mexico that are within a day’s drive of the border, but still…
They already do, and they always have. I’m baffled that so many people who apparently have crossed the border with some frequency seem to think otherwise. And birth certificate + photo id is really just not that onerous a burden. The mandatory passport rule scheduled to take effect next year will be a bit of a pain, though.
My understanding is that US vistors to Canada who arrive by air from the US need to show a passport, while this is not true of crossing by car.
Yup, that’s all you need right now to get into the US, but be prepared for a (potential) small delay and a bunch of questions, especially if you’re travelling alone. I have a passport, but recently flew to Hawaii without it. Going there was fine, as I was travelling with friends. Coming back, I was all alone, and had to answer 15 minutes of questions like “Who bought your ticket for you?”, “Married or single?”, “What did you do on your trip?”, “Did you purchase alcohol?”, “Where do you work?”, “What are you studying at university?”, and so on. Which, whatever, I wouldn’t have minded, but I’d just stepped off a sleepless 6-hour redeye flight and just wanted to sit down.
And obviously, this won’t happen to everyone all the time, but it’s more likely if you don’t have the passport. And I think they’re worthwhile to have, especially if your wallet gets stolen or you lose your driver’s license.
I’m not actually super worried - I look very honest, and much to flashy to be trying to pull anything over on anyone. Well, at least that’s how it’s always worked out in the past. 
Well, I guess I’m baffled too, because I have driven back and forth across the border my whole life (I’m 38) and have never, ever, not once been asked for proof of US citizenship. Flying recently has been a different story, but driving? Never.
Obviously, my mileage has varied, considerably.
FWIW, this has been my experience when going to Canada. Only rarely was I asked for my birth certificate. I finally got a passport late last year, so I’ll be good when they become mandatory.