60 percent of Americans believed at least one of the following: clear evidence had been found of links between Iraq and Al Qaeda; W.M.D. had been found in Iraq; world public opinion favored the U.S. going to war with Iraq.

The prevalence of these misperceptions, however, depended crucially on where people got their news. Only 23 percent of those who got their information mainly from PBS or NPR believed any of these untrue things, but the number was 80 percent among those relying primarily on Fox News.

The problem with Mr. Murdoch isn’t that he’s a right-wing ideologue. If that were all he was, he’d be much less dangerous. What he is, rather, is an opportunist who exploits a rule-free media environment — one created, in part, by conservative political power — by slanting news coverage to favor whoever he thinks will serve his business interests.

In any case, do we want to see one of America’s two serious national newspapers in the hands of a man who has done so much to mislead so many?