Packed though it may be with aides, pollsters and consultants, the campaign bus can be a lonely place for a candidate chasing the keys to the White House. But Mitt Romney, this year's Republican runner, is preparing at last to make some room in the front for someone to join him, hip-to-hip, for the rest of the journey.
Exactly when Mr Romney means to roll out the running mate he hopes will help him unseat President Barack Obama is a point of speculation almost as urgent as guessing who that person might be. "Person" is used advisedly. It's the word Mr Romney used in comments to NBC last week.
Cue cable television pundits' chorus: it's a woman! But any other hints about who he wants as the No 2 on his ticket were not forthcoming. "I certainly expect to have a person that has strength of character, a vision for the country that adds something to the political discourse about the direction of the country," the former Governor of Massachusetts averred flatly.
The Romney campaign has been actively stoking the Veepstakes suspense at a time when the campaign conversation has in all other respects not been kind to the candidate, particularly after he was seen to have botched his trip to Britain, Israel and Poland. They have even signed up supporters to a Veep-Pick smartphone app with the promise they will learn of his choice before anyone else. Users of the app will be especially vigilant this weekend as Mr Romney departs his Boston campaign headquarters for a high-profile bus tour of four key battleground states, starting with Virginia today and passing through North Carolina and Florida before ending in Ohio on Tuesday.
The window for the big reveal is getting narrow – it must happen before the Republican Party convention which opens in Tampa in two weeks.
The final decision rests with Mr Romney alone and in the end it could be that he picks someone the rest of us haven't thought about – a general, a mayor or an industrialist. There is a list of possibles and probables the media has settled on, but deciding who should be at its top continues to be a highly vexing game. A CNN poll says Republican voters favour Marco Rubio, a Cuban-American US Senator and Tea Party darling from Florida. The market site Intrade has its money on Rob Portman, a US Senator from Ohio, while the conservative wing of the party is pressing for Representative Paul Ryan.
Mr Ryan, the House budget chairman, is the author of his party's budget blueprint for the country that is as bold as it is controversial, taking a long blade to such sacred cow social programmes as Medicaid and Medicare. Conservatives think he will keep Mr Romney fiscally honest.
Another in the ring is Tim Pawlenty, a steady, if unexciting, former Governor of Minnesota who made his own run for the party nomination before dropping out last summer.
Any talk of a woman joining the ticket provokes nostalgic exchanges about the circus of bemusement – and some amusement – that erupted when, just four days before his convention in 2008, John McCain introduced the world to Sarah Palin. But Mr Romney is seen to have options that would invite no comparisons with the former Governor of Alaska. Among them would be Condoleezza Rice, the former Secretary of State, Kelly Ayotte, a newcomer to the US Senate from New Hampshire, and Susana Martinez, the Governor of New Mexico.
Someone else who might placate the Tea Party wing is Mike Huckabee, a Southern Baptist evangelist who fought Mr McCain for the nomination four years ago. He is affable, articulate and socially conservative to his marrow. But now it is the Ryan star that seems to be burning the brightest, thanks to a big push from, among others, the editorial writers of the Wall Street Journal.
"The House budget chairman has defined those stakes well as a generational choice about the role of government and whether America will once again become a growth economy or sink into interest-group-dominated decline," the Rupert Murdoch-owned newspaper opined last week.
Runners and riders: The likely names
Job Ohio senator
Pros A solid conservative, he would appeal to the Republican masses, and his experience as director of the Office of Management and Budget for the Bush administration makes him odds-on favourite to join Romney's ticket.
Cons Critics say he is, to put it politely, a tad dull.
Odds 2/1 (Ladbrokes)
Job Florida senator
Pros The favourite among Republican voters, Rubio is well liked in the Washington rumour-mill, and is doing well in the online betting stakes too. A Hispanic rising star of the Tea Party, he has wide appeal.
Cons As a first-term senator, he may lack the gravitas that others could lend to the Romney camp.
Job Governor of New Mexico
Pros Touted as one of the Republican Party's most popular governors, she has the added strengths of being Hispanic and a woman. She is still regarded as a possible surprise nomination, not least because Romney himself name-dropped her as a potential candidate in January.
Cons She has publicly stated that she is not interested in the post.
Job Wisconsin congressman
Pros Many speculated that the House Budget chairman's introduction for Romney after his victory at the Wisconsin primary, which attacked President Obama for his "broken promises", proved his might and perhaps even sealed the deal.
Cons Some Republican insiders now doubt that Ryan – a career politician – has what it takes.