Something I see as more likely than not eventually. Probably taking the form of blocking all encrypted traffic for which no usable back-door can be readily verified.
That will work until some ingenious hacker finds a way to get into the back door or some corrupt government employee sells all the private keys to the Russian Mafia, and then you can say goodbye to e-commerce, full stop.
It's a stupid idea even for a government.
It's certainly not a new idea. Thankfully it has been rejected thus far (thanks in large part to the efforts of people like Hal Finney) but desperate times require desperate measures, as they say.