Barack Obama should be thankful that the Wall Street crisis is dominating the news these days, because otherwise more people might notice that he has been uttering manifest falsehoods about John McCain's Social Security plan - in a bid to woo the potentially pivotal senior voters who remain cool to Obama's historic candidacy.

While on the stump in Florida last weekend, Obama contended that McCain's talk of Social Security privatization could leave seniors destitute: "If my opponent had his way, the millions of Floridians who rely on it would've had their Social Security tied up in the stock market this week. Millions would have watched as the market tumbled and their nest egg disappeared before their eyes."

Obama lied. No such nest eggs would have disappeared, because the McCain plan exempts every American born before 1950. I could also detail the Obama TV ad on Social Security that has been aired in Florida, Pennsylvania and five other states - it falsely claims that McCain favors "cutting benefits in half" - but here's the point:

The Obama camp has apparently decided that the candidate needs to scare senior Americans into voting for him, because he doesn't appear to be connecting with enough of them any other way. Voters 65 and older are less charmed by Obama than any other age bracket; their resistance - particularly in battleground states such as Florida (the grayest state), Pennsylvania (second grayest), and Ohio (eighth) - is a potentially serious drag on his November prospects.

The latest nonpartisan Pew Research Center poll shows plus-65 voters favoring McCain over Obama by five points; the higher the age bracket, the lower the percentage share for Obama. It's worth noting that, on Election Day four years ago, plus-65 voters favored President Bush over John Kerry by five points. It's also worth noting that Al Gore in 2000 and Bill Clinton in 1996 defeated their respective opponents in the national popular vote in part because they won the senior vote.

Obama fans might say, So what? We're going to reshape the electorate by turning out young people in unprecedented numbers. What we lose in the top age bracket, we'll make up at the lowest.

I'll believe it when I see it, and here's why: Federal census figures show that 69 percent of all eligible seniors turned out to vote in 2004; only 42 percent of eligible 18- to 24-year-olds bothered to show up. It strains credulity to assume that a historic flood of young people will significantly narrow a turnout gap that has surfaced in every census table since the 1980 election.

So attention must be paid to the seniors. While stipulating, of course, that seniors are not monolithic. The small-town, blue-collar Pennsylvania senior is not to be confused with the tennis-playing Florida aficionado of the early-bird special. Millions of older voters remain wary of Obama for reasons that may be tough for him to dispel in a mere 36 days.

Some of the danger signs appeared during the Democratic primaries, when seniors consistently favored Hillary Rodham Clinton by landslide percentages (Obama's deficit in Pennsylvania's primary was 26 points). They did so not just because they viewed Obama as insufficiently experienced, or too "exotic" for their traditional tastes, but because his constant heralding of a "new" movement tended to make a lot of them feel old - and left out.

As one 68-year-old told his Florida newspaper this summer, "When you keep talking about tomorrow, people who are older start feeling like yesterday."

Obama's "change" mantra has been another impediment. Seniors - unlike young people, with their limited time horizons - don't necessarily see "change" as intrinsically good. They've lived through good changes, and bad changes, and promised good changes that turned out to be bad changes. A recent Pew poll reports that only 53 percent of seniors find Obama inspiring - again, the lowest score of any age bracket.

And seniors today may be more conservative in temperament than in the recent past. It's a matter of demographics. When Bill Clinton won in 1992 (and captured the senior vote), the typical 70-year-old was someone who grew up during the FDR New Deal era and developed Democratic voting habits. The current 70-year-old grew up during the Eisenhower era as a member of the so-called Silent Generation - just like John McCain. Many of these seniors today can relate to McCain as one of their own; unlike Obama, who, fairly or not, is still widely viewed as a kid who cut to the front of the line.

Hence the attention Obama is now paying to seniors. He needs them to nail down Pennsylvania (a state that should be his anyway), and, above all, he needs them to snatch Florida away from McCain.

If he can do the latter, it's hard to see how McCain can win this election. But Florida polls, as elsewhere, still show Obama trailing among seniors, which perhaps explains his factually challenged flailings - such as the claim that McCain wants to slash Social Security benefits "in half," whereas, in reality, the number of current seniors affected by McCain's plan add up to zero. And there's no evidence that McCain is talking about future 50 percent cuts for anyone.

Obama has come this far by marketing hope, yet his current pitch to seniors is based on fear. It's stark evidence that he has yet to close the sale with a crucial slice of the electorate - and that he is willing to dissemble rather than inspire, if that's what it takes.