Casino opponents in Holyoke are stunned and infuriated by Mayor Alex B. Morse’s reversal of his longstanding anti-casino positions, and promise a fierce political fight as they renew their resistance to a gambling resort in their city.

“This was a calculated betrayal on the mayor’s part,” said resident John P. Epstein, a staunch casino opponent who supported Morse’s 2011 campaign for mayor. “He would not have been elected without the efforts of the anti-casino citizens in Holyoke. We have been caught completely off guard.”