Right now, with Hillary Clinton leading the race for the Democratic presidential nomination and questions lingering about her electability in the general election, some Democrats have daydreamed a what-if (or if-only) ticket: Al Gore for president, with Barack Obama as vice president.

The main problems with the idea are (1) Gore says he isn’t running (and it’s way too late to build a campaign apparatus and make filing deadlines for the primaries), and (2) Obama is running for president, not vice president. That leaves fantasists to dream of a Gore-Obama ticket emerging from a brokered convention.

Is it possible? Barely, say the experts. To win the Democratic nomination, a candidate needs a majority of votes from convention delegates. If no candidate wins a majority, no one really knows what would happen in the modern day. In the old days of presidential conventions, many candidates would still be vying for the nomination at the convention. Groups of delegates would negotiate to shift votes, often in exchange for patronage. Sometimes a compromise candidate who hadn’t been a front-runner would emerge with the nomination—as was the case with Abraham Lincoln (good choice), Franklin Pierce and Warren G. Harding (disasters), and James Polk, the country’s first dark-horse candidate.

In the fantasy scenario, Clinton, Obama, and John Edwards each get a chunk of delegates, but none gets 50 percent. At the deadlocked convention, Democrats somehow turn to Gore. “I think it’s more likely than being hit by lightning but not much,” says Denison University’s Emmett Buell Jr., an expert in presidential nominations.  “Put me down as an extreme skeptic.”