A CNN poll released Friday shows Hillary Clinton leading John McCain in a trial heat:

If presidential elections were held today, Sen. Hillary Rodham Clinton would likely have a comfortable edge over Sen. John McCain, but take away her maiden name and McCain has a better shot of landing in the Oval Office.

So say the results of a CNN poll released Friday by Opinion Research Corp., which asked 506 adult Americans whom they preferred among potential 2008 presidential candidates. The margin of error for the survey is plus or minus 4.5 percent.

Asked if they preferred Hillary Rodham Clinton to McCain, respondents gave the Democratic New York senator and former first lady a 51 percent to 44 percent advantage over the Republican Senator from Arizona. Remove “Rodham” and McCain had a 1 percentage point advantage, 48 percent to 47 percent.

The CNN.com article gives no indication, however, that previous polls have consistently shown McCain defeating Clinton in trial heat matchups. If we assume that half of CNN’s respondents received her middle name and half did not, we can combine the results and find that Clinton led overall 49 percent to 46 percent. These results are way more favorable than previous surveys for Hillary:

It’s certainly possible that she’s making up significant ground — as I’ve said, McCain’s support will inevitably erode as Democrats become more critical of him. However, it’s more likely that the CNN results are a product of an extremely favorable political environment. Hillary’s consistently polled behind McCain, and I expect that pattern to continue after November 6.