If not Clinton, would Martin O'Malley fit the bill?
It is a question that nags at Democrats who know that the long road to the White House is littered with the remains of front-runners who failed to finish: if not Hillary Clinton, then who?
Step forward Martin O'Malley, the two-term governor of the state of Maryland and former mayor of Baltimore. His biggest - indeed only - claim to national fame is that he was the inspiration for Tommy Carcetti, the fictional crime-busting mayor in the gritty HBO crime series 'The Wire', played by Irish actor Aidan Gillen.
Flashing a Carcetti-like smile, Mr O'Malley was out in the bellwether state of New Hampshire, plugging his record of creating jobs in Maryland and cleaning up Baltimore, the port city that became notorious for its runaway drug and crime problems in the late 1990s.
"We had allowed our city to become the most violent, the most addicted and the most abandoned city in America.
"And against that backdrop I decided to try. I ran for mayor," Mr O'Malley (52) told an audience of business and political insiders in the small town of Bedford.
"We proclaimed from a notorious drug corner that there is more that unites than divides us.
"And that the forces of hope and despair can no longer co-exist on the corners of our streets."
The vast majority of Americans have never even heard of Mr O'Malley - he polls at just 1.2pc in the Democrat nomination race, compared to nearly 60pc for Mrs Clinton - but, come November when presidential race gets under way, he dreams that they might. "History is full of times when the front-runner is inevitable," says Mr O'Malley when asked about why he's even bothering to campaign given his near-zero poll ratings, "right up until he or she is no longer inevitable." In essence, if Mrs Clinton stumbles or drops out with a health issue or a major scandal, then Mr O'Malley will be waiting in the wings, ready and prepared to take the under-study's call.
If only by default, the spotlight is beginning to fall on Mr O'Malley's youthful, tanned features since a cursory assessment of the other potential Democrat runners shows he has precious little competition for the role. With Mrs Clinton expected to declare tomorrow, having already snapped up the best operatives and locked in fundraising that Republicans fret could top $2bn, time is running out for would-be challengers to mount a campaign.
The only other recognisable Democrat figures - Joe Biden, the vice president and Elizabeth Warren, the high-profile banker-bashing senator from Massachusetts who both poll at around 12pc - show no signs of running.