Mark twain's quote on politicians

Photo c/o azquotes.com

I really don't know the context behind what Mark Twain was quoted as saying: politicians and diapers must be changed often, and for the same reason.  Did he have a terrible time dealing with politicians? What would have been his experience with politics and politicians?  Was he disillusioned, disgusted, frustrated, dismayed, and devastated by the shenanigans of the politicians of his time?

I've been trying to do a bit of research about this but I just couldn't find any confirmation on this quote. It is a great quote for people aspiring for public office, and a cheeky way to get the attention of voters.  I've seen on the web certain personalities and politicians using this quote in their speeches.  It does make for a good conversation piece and with the media landscape nowadays, media handlers for politicians can use this to make for a good sound bite.

I do have friends who are into politics and politicians who are my friends. I was active in school politics, that at one time, I even entertained the notion of running for public office.  We didn't have any of these shady deals that seems to be the norm for politicians now.  Well, perhaps because we were just promdi, school-based or was it rather that the 60's and 70's were different then?  I've done heaps of consultancy work for the Office of the President from FVR, Erap to PGMA, and was privy to some high-level politics.  I've done projects with cabinet secretaries, senators, congressmen, governors, mayors, colonels, generals, and even barangay captains.  And I invoke what showbiz columnist Maurice Arcache says, my lips are sealed.