The John Edwards campaign has just distributed a new "interested parties" memo. Its subject line is "Path to the nomination," and we were looking forward to reading the rest: Having not yet won a state, having lost badly in first-in-the-South South Carolina and trailing far behind in the delegate count, how can Edwards win the Democratic presidential nomination?

We've read the memo, and we're still not sure.

The "path to the nomination" seems to be as much of a hope as it is a plan. The Edwards campaign says an "online fundraising boom" has left it on "solid financial footing," but it understates Edwards' delegate deficit by focusing only on the delegates won in Iowa, New Hampshire, Nevada and South Carolina and by ignoring the super-delegates who have already aligned themselves with a candidate. By the Edwards campaign's way of counting, Barack Obama leads the delegate count with 63, followed by Hillary Clinton at 48 and Edwards at 26. By CNN's tally, Clinton has 230, Obama has 152 and Edwards has just 61.

Either way, it's a long way to the 2,025 needed to win the nomination. How does Edwards get there? The Edwards campaigns say it expects that the Democratic presidential race "will narrow to one of the two celebrity candidates and us -- and when that happens, we are confident that the remaining contests will break in our direction as voters are finally offered the choice the national media has ignored all year -- the most progressive, most electable candidate in the race, John Edwards."

That's not an unreasonable scenario if you assume away the premise -- that is, if you simply assume that at some point one of the "celebrity candidates" ceases to be a serious contender. But what's the basis for making that assumption? On what set of facts would either Hillary Clinton or Barack Obama drop out of the race and leave Edwards free to face the other alone? That's the critical assumption underlying the Edwards' argument, and the justification for making it isn't in the memo.