This malaphor was written by Michael Gerson in a Washington Post column. https://www.washingtonpost.com/opinions/the-best-fortnight-in-a-decade-for-conservatives-uh-oh/2017/02/06/93e2f1aa-ec9a-11e6-9973-c5efb7ccfb0d_story.html?utm_term=.fe5334ede362
It is a nice mash up of “on the horns of a dilemma” (unable to decide between two things because either could bring bad results) and “bull in a china shop” (clumsily destructive). Mr. Gerson was discussing how Republicans are in a difficult situation, where if they criticize Trump, they could receive massive retaliation. While malaphors are usually unintentional slip ups, this one clearly was not. A big thanks to Sam Edelmann for seeing this one and passing it on!