Stuart Campbell, who posts online as Wings over Scotland, has began civil court proceedings to recover $100 from John McTernan, a political analyst and pollster.
The duo had clashed on social media over the recent US presidential election won by Donald Trump.
Campbell suggested whichever candidate McTernan backed would inevitably lose.
He wrote: “Nobody has ever been as doomed as Hillary Clinton is now #McTernanPredicts.”
Mr McTernan offered the $100 stake in response, to which Campbell replied: “You do everything in dollars now, John? By November that could be £500. But at today’s exchange rate of £76, you’re on.”
“It’s shocking that I’ve had to do this,” Campbell told The Scottish Sun.
“John McTernan’s dignity and honour are clearly about as substantial as his skills as a political analyst.”
The bet was agreed in several tweets posted in the summer.
Campbell from Bath, Somerset, is now reportedly chasing £101 — including £25 for lodging a claim — through the English courts.
Mr McTernan has been approached for comment.