THE DREADED SEPTUAGENARIAN ISSUE…. There’s a new Washington Post/ABC News poll out this morning, and it appears to be the last major national poll before the presidential race shifts gears (it was taken before the Biden announcement and on the eve of the Democratic convention).

Given that the campaign is probably about to change, at least a little, it’s hard to know just how much predictive value, if any, a poll like this is going to have. For what it’s worth, it shows Barack Obama leading John McCain by four among likely voters, 49% to 45%. The lead is slightly bigger among registered voters, 49% to 43%.

But looking through the data, there was one set of questions that jumped out at me:

“If elected, McCain would take office at age 72. If you honestly assessed yourself, is that something with which you’re entirely comfortable, somewhat comfortable, somewhat uncomfortable or entirely uncomfortable?”

The same poll also told respondents, “If elected, Obama would be the first African-American president,” followed by the identical question about voters’ comfort levels.

Interestingly enough, 87% said they were comfortable with an African-American president, but 55% said the same about a 72-year-old president. Moreover, while 11% conceded they were uncomfortable with an African-American president, 45% said the same of a 72-year-old president. Only 6% said they were “entirely uncomfortable” with a black president, while more than triple, 20%, said the same of a septuagenarian.

Now, I don’t doubt that some respondents were being less than honest about their racial prejudices, but even putting that aside, that’s a lot of people who are obviously uneasy about McCain’s advanced age.

I continue to think this is something of a sleeper issue in this campaign. There’s been enormous interest in exploring the racial angles to this campaign, but there’s ample data — going back to early last year — that McCain’s age actually matters to voters, and it’s an issue that raises doubts.

Something to keep an eye on.

Our ideas can save democracy... But we need your help! Donate Now!

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.