Barack Obama, who is struggling to recapture the early promise of his presidential campaign, is sending his wife, Michelle, to London next week to try to generate cash and excitement for a bare knuckles fight against Hillary Clinton.
Ms Obama's visit will be fleeting, but the timing is crucial. Even her husband admitted on Thursday that Ms Clinton, with her lead in polls, fundraising and endorsements, had become the "default candidate" for Democrats, and that he needed to take her on more directly.
In London Ms Obama will attend a $100-a-head fundraiser on Monday at the Landmark Hotel in Marylebone. The event will be preceded by a more exclusive gathering for "bundlers", those who raise contributions of $23,000 (£11,300) or more for the campaign. She returns to the US on Tuesday morning.
The campaign hopes that the visit to London - sympathetic terrain for Mr Obama, who leads all of the 2008 presidential contenders in overseas fundraising - will help to rekindle the early excitement about the prospect of electing the first African-American president.
With the stakes so high in the three months before the first primary votes are cast, Ms Obama is unlikely to fall back on her comedic routines of this summer. In Iowa and New Hampshire, Ms Obama, 43 and an executive at the University of Chicago hospitals before she gave up her job earlier this year, would chide her husband for failing to pick up his dirty socks or put the butter back into the refrigerator.
But the time for jokes about Mr Obama's domestic foibles is long past, his campaign admits. It also acknowledges that Ms Obama's grousing about her husband may have backfired, amplifying doubts that he has the experience or gravitas to lead the free world.
Ms Obama's mission now is to make her husband appear presidential. "She will be talking about her husband as the person who knows him best, from her personal perspective, on his judgment, his experience, and his strength as a leader. After all, she has known him for 20 years, and she is going to talk about that consistency," her spokeswoman, Katie McCormick Lelyveld, said.
She will also talk about the Obamas' life at home with their two young daughters, fleshing out her husband's political resume and drawing a sharp contrast with Ms Clinton's famously troubled marriage.
Ms Obama's trip to London brings a rare absence from her children. In the past, she has said she wanted to return home each night to Chicago to put the girls to bed.
But Mr Obama is running out of time to prove himself against Ms Clinton and the other Democratic contenders. An opinion poll for National Public Radio yesterday for the first time rated Ms Clinton more electable than Mr Obama against a Republican opponent. Ms Clinton also won endorsement yesterday from John Lewis, a civil rights era activist and African-American congressman.
Mr Obama's supporters complain that he has failed to capitalise on the early excitement of his candidacy. He acknowledged their frustration on Thursday, telling CNN: "Now is the time where we're going to be laying a very clear contrast between myself and Senator Clinton."
The overseas fundraising jaunt for Ms Obama would once have been seen as unseemly for a political spouse, but with the presidential contenders set to spend $1bn between them between now and November 2008, every dollar counts.
In the first six months of this year, expatriates donated $471,000 to presidential candidates, a report by the Centre for Responsive Politics said, nearly as much as was donated in the entire 2000 election season. Most was raised in London, which accounted for $270,000.
The biggest beneficiary by far was Mr Obama, who raised $194,000 outside the US. Rudy Giuliani took in $119,000, and Ms Clinton $51,000.
Profile
Michelle Obama: Born 1964 to a secretary and a pump operator on Chicago's south side. Degrees from Princeton University and Harvard Law School. Associate at Chicago law firm Sidley & Austin, where she mentored Barack Obama. Married in 1992 and with two daughters, the couple live in a $1.65m (£810,000) home in Chicago. She is an executive at University of Chicago Hospitals. Rises at 4.30am to run on a treadmill. On Vanity Fair's best-dressed list.