We got Cardi outside The London NYC on Thursday and asked about Offset's hope for a potential Kim K presidential run ... and Cardi reveals Kim's been thinking about politics for some time.

She strongly insinuates she and Kim talked about the presidency, and tells us that's the real reason why Offset says he'd vote for KKW.

Cardi and Kim kicked it back in early August, so we're thinking that's when they chopped it up about politics. Kris Jenner was there too, and you know she's always got something in the works.