I first heard "is, is that..." used by the President. "The thing is, is that..." or "My decision is, is that..." or " The thing we all have to understand is, is that...". This drives me nuts. Now, I hear the usage everywhere, particularly in the spoken media. What is happening here? This can't be correct
It sounds like a lazy way to sound pompous.
There are more sympathetic interpretations for it though in a previous discussion on the exact same topic that sorry I couldn't retrieve.
There's another one-
I can't copy the link to it here, so I am replying to bring it on like a separate topic.
I first started hearing this in the late '80s or so, I'd guess. I assumed at the time—and it still sounds to me like a reasonable theory—that it started as a pause in spoken thought. "The thing is...<pause for thought>...is that I didn't want to seem..." and so on. But now I hear people, and reasonably polished speakers too, saying "the thing is is that I didn't want to seem..." without hardly a comma before the redundant word.
I don't believe pomposity is intended, though. I don't think that people who do it are aware of it.