SAGA, Japan—The Fukushima Daiichi accident was a big setback for nuclear power in Japan. But the industry's hamfisted efforts to maintain support in the aftermath of that disaster may have an even bigger impact in eroding the public's confidence in the sector.

After a series of disclosures in recent weeks painting government regulators and electric utilities as collaborating to stage-manage public community forums on local nuclear power, efforts to restart idled Japanese nuclear reactors have screeched to a halt.

The...