If there's one thing that John McCain does not want to spend time talking about, it's Viagra.
Barack Obama can make breezy stump jokes about adverts showing happy couples skipping through fields. For the 71-year-old Arizona senator, however, there's just no upside to any focus on the pharmaceutical product of choice of Bob Dole, the last battered war veteran to run - rather haplessly - for president.
But there was no excuse for McCain's excruciating discomfort when asked about Carly Fiorina, a top ally, blasting insurance companies for covering erectile dysfunction drugs but not birth control.
Her comments had already attracted controversy and the issue is one close to the hearts of many women. McCain should have had a ready, fluent response.
Instead, the eight-second pause and the protestation that he could not give an "informed answer" because he could not "recall the vote right now" played right into the narrative that McCain is old, out of touch and has been in Washington so long that he can't even remember what he's done there.
While Obama usually seems at ease and ready with a quip or a smile, in formal settings McCain can sometimes look as if he's in pain. If he does grin, he looks more like Jack Nicholson in "The Shining" than a candidate actually enjoying himself.
The Viagra episode showcased a politician with clear shortcomings in a 21st Century general election. It's one thing to get by as the maverick shooting the breeze with reporters on the Straight Talk Express when you're the underdog in New Hampshire, but it's quite another when you're the under the klieg lights as the nominee.
When asked what he would do to attract female voters, McCain could do no better than respond: "I don't have a specific policy at the moment, except to, again, I think my support of small business and the fact that I will not raise people's taxes." Not exactly an answer to inspire.
An even more serious problem for McCain is what the Viagra episode revealed about his broader campaign. Prepping him for the question was a basic piece of campaign staff work that had apparently been overlooked.
The gaffe could have been avoided, furthermore, if Fiorina had not denounced a policy that her own candidate had voted for in the Senate.
Hers wasn't even the worst gaffe by a top McCain surrogate this week. Phil Gramm's ramblings about a "national of whiners" and a "mental recession" were a gift for Obama - insulting the voters and denying an economic slump that working Americans know is not just in their minds.
After previously admitting that the economy was not his strong subject, McCain could have certainly done without that. And by denying that Gramm, his most senior economic adviser, was speaking for him, McCain's reputation for straight talk took a bit of a hit.
Unfortunately for Republicans, the mistakes are not just tactical. As well as being disorganized, his campaign lacks strategic direction and its messaging can at times be inept.
Describing Obama as a "typical politician" and "just another politician" seems a woefully inadequate response to his astute move to the centre. If anything, it helps blunt a potential Obama weakness - that he lacks the experience to operate in Washington. And the Illinois senator's race, charisma and compelling life story make it that much more unlikely this type of label will stick.
Rudy Giuliani, another McCain ally, tried a different tack last week when, responding to Obama's remark that Americans need to learn foreign languages as much as immigrants need to learn English, he suggested that Obama was capturing an "anti-American feeling", as illustrated by his popularity in Europe.
Obama certainly has vulnerabilities on foreign policy, and the concerns from Chancellor Angela Merkel about a possible Obama speech at the Brandenburg Gate in Berlin illustrate the dangers his faces on his European trip. Any suggestion of electioneering abroad - or a visible manifestation European Obamamania - could be very bad politics in the American heartland.
But the charge that Obama's popular campaign is the result of capturing some "an anti-American feeling" is highly unlikely to wash. His story is in many ways the quintessential American Dream - mixed race, raised by a single mother on food stamps and by his grandparents, a political nonentity just eight years ago who could not get a convention floor pass.
The Republican strategist Alex Castellanos recently told me what he believed the Republican bumper sticker against Obama should be: "A risky choice in an uncertain world."
With an ailing economy, unpopular war and unpopular Republican president and in face of superior Democratic enthusiasm and fundraising, that might not be enough to win the White House. It would, however, be a more coherent message than anything Team McCain has come up with.
He's already had a staff reshuffle but McCain's campaign is in dire need of a shot of political Viagra.