In order to win the nomination, how many earned delegates does Sen. Hillary Clinton have to win?

It's not an academic question. With a little spreadsheet math, we can figure it out.

We need to start with some assumptions.

First, let’s be generous and assume that all of the superdelegates Clinton currently claims will not switch to Obama.

Perhaps that’s an overly generous assumption given that two have done so over the past two days, but, again, we’re trying to illuminate a path to the nomination, not block one. Let’s assume that, all other things being equal, she’ll win half of the remaining uncommitted superdelegates – maybe 185 of 390. She’ll also win half of John Edward’s delegates.

Before we move to pledged delegates, we need to figure out whether Florida and Michigan delegations are credentials and what effect they’ll have on the nomination. At this point, it’s most likely that they will be segregated from the official nomination scenarios.

So – just for the moment – let us calculate the number of remaining 981 pledged delegates Hillary Clinton would need to earn in order to win the nomination without the help of Michigan and Florida.

Assuming that her currently total is 1275 – a nice amalgam of the various network and print delegate estimates, she needs at least 55.3% -- or about 542.

Let’s go to March 4. Let’s assume that Clinton wins Ohio by four points – 52 to 48, netting her roughly 5 extra delegates, and loses Texas 49 to 51, netting Obama three extra delegates, and loses Vermont, netting Obama three extra delegates, and winning Rhode Island by 6 points, netting herself an extra delegate. She ends that day with no additional delegates – she can blame Vermont.

Under the rosiest of scenarios, it’s hard to see her winning more than about 50 percent of the remaining earned delegates, even if she whips Obama in Pennsylvania and earns, say, 16 extra delegates, and drums him in Puerto Rico, where, even if she wins seventy percent of the delegates, she’s still, in essence, playing catch up.

If Clinton wins half of the remaining delegates – about 493 – and loses none – she still trails Obama by a net 50 or so earned delegates.

Now let’s run the scenario with Florida and Michigan’s delegates in play – the best iteration of that scenario, with both pledged and unpledged delegates seated and Clinton’s having earned fully 60% of or more of them. She’ll need at least 52.1% of remaining pledged delegates to surpass Obama.

Playing with the numbers a bit, here’s how she could – in theory – accomplish this.

If Florida and Michigan's delegations are seated fully to her advantage, and if she wins in Ohio by 65% and wins in Texas by 65%, and all other percentages hold, she can win the nomination.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.