No problem. It would be gone. . . and you could do it from your iPhone or iPad. Apple uses military grade deletions. Try that if they had your computer and you no longer had possession. Of course, if you used a good passcode and 256 bit AES encryption, they'd have a hell of a time getting at it, no matter where you put it. Although it would be overkill, Apple allows everyone of the 227 characters available on the keyboard to be used in their passcode and the passcode can be 256 characters long. That means the possible combinations of your Apple iCloud COULD be one of something under (because you can't have two of the same characters side-by-side) 227256 combinations. I wouldn't want to try and remember a passcode that long. . . but you could if you want to.
Cryptographers tell us that to break such an encryption, assuming making 50 attempts per second, the amount of time to break in would exceed the time left before the Universe dies from heat death. Oh, did I mention, you get locked out after five failed attempts?
Apple then takes YOUR encrypted data which uses your personal key, anonymizes it, and then adds ANOTHER level of 256 bit encryption on top of that, using THEIR KEY, breaks it into smaller batches, uses a algorithm to randomly store your data along with other user's encrypted data, in their own and leased data farms. IF the government demands the data, all they get is piles of encrypted gobbledygook, that may or may not include your encrypted gobbledygook. Without your key, they have no way of knowing what's in it.
“Could do it”
How about it already having been done when he thought it was done.
Some people might want persistent files, and more power to them, but this ought to be an opt-in service that gets in your face and explains itself starkly.