The Rocky Mountain News’s coverage of John McCain’s campaign stop in Denver last week raises an important issue for reporters, especially those covering the election: Do you let a candidate’s remarks stand unchallenged even if they are wrong or misleading?

McCain had come to town to talk mostly about health care, the paper reported, noting that the topic took up a large part of his hour-long speech. The News offered all too typical coverage of such talks, however—bits and pieces on a lot of topics, with quotes here and there. We do learn that on health care, McCain urged states to take a leadership role in reform, and that he pumped his tax credit aimed at helping Americans buy health insurance. In the next graph, the paper said that McCain’s rationale for the tax credits “is that making major reforms and using government to work through the problem will affect the quality of coverage for Americans—which he called the best in the world.”

The best health care in the world? McCain has asserted that before and so have other politicians. No doubt we will hear it again. But the evidence says otherwise. The Commonwealth Fund, which each year compares the U.S. system to those of other countries, has found serious shortcomings in the American way of health care. Among other things the study concludes that “The U.S. health system is the most expensive in the world, but comparative analyses consistently show the United States underperforms relative to other countries on most dimensions of performance,” including quality, access, efficiency, equity, and healthy lives. “Among the six nations studied—Australia, Canada, Germany, New Zealand, the United Kingdom, and the United States—the U.S. ranks last.” The study provides a great deal of detail.

Meanwhile, a large proportion of voters are beginning to question the quality of our nation’s health care system, presumably based on their experience. A while back the Harvard School of Public Health and Harris Interactive polled voters and found only 45 percent said that they consider the U.S. health care system the best in the world. Thirty-nine percent said other countries have better systems, and 15 percent said they didn’t know or didn’t answer the question. (The poll also found that Republicans were more likely than Democrats to believe the U.S. system was the best).

So McCain’s statement—which he repeats often, and which has the effect of suggesting that serious reform may be uneceessary, or that it could cause more harm than good—needs to be tested in the media, and often.

Earlier this week the New York Times public editor Clark Hoyt, who hears from hundreds of readers every day, told journalism students at Baruch College in New York that “readers are looking for history, context, and analysis.” In this case, the Rocky Mountain News sure didn’t give its readers any of that. I asked Hoyt, who for many years was an editor for Knight-Ridder, whether journalists should set the record straight when candidates omit the real story. “There should be more of that,” he said and offered a reason why it’s often not done. “A newspaper will report something once, and think they’ve already done that. But new people are coming to you all the time. Some things you need to keep repeating.”

Presidential candidates know that repetition works, and that’s why we hear the same words and themes in speech after speech—McCain and his best-in-the-world health care; Clinton and her use of “universal coverage”; Obama saying he never takes money from lobbyists. They know that if voters hear the same message often enough, they will believe it, even if it is less than true.

Journalists must also repeat, therefore. We must add history, context, and analysis, and when something is flat-out wrong, we should say so. The topic of American health care quality is a good place to start. And to repeat.

Trudy Lieberman is a fellow at the Center for Advancing Health and a longtime contributing editor to the Columbia Journalism Review. She is the lead writer for The Second Opinion, CJR’s healthcare desk, which is part of our United States Project on the coverage of politics and policy. Follow her on Twitter @Trudy_Lieberman.