During John Edwards’ remarks to an annual forum of his fellow trial lawyers in Chicago on Sunday, the former senator spoke passionately about civil justice issues, joked about “that little house that we have in North Carolina” and warned of “a very concerted, very orchestrated radical right agenda” to “hijack the jury system.”

He also, ever so gently, made the political case for the viability of his presidential campaign.

“It’s not enough for you to like a candidate,” said the former trial lawyer, tanned and comfortable in his sharp blue suit. “It’s not even enough for you to agree with a candidate. We must—my party, the Democratic Party—we must nominate a candidate who will win the general election.”

After receiving a standing ovation, and blowing two-handed, operatic kisses to his adoring colleagues in the audience, Mr. Edwards retired upstairs to the Hyatt Regency’s Crystal Ballroom, where he expanded on that political theme for about 50 supporters, many who had paid $1,000 a head.

Amongst friends and fund-raisers, he was much more blunt.

“All the empirical evidence shows that I am the strongest general election candidate,” said Mr. Edwards from a small stage as the Chicago traffic flowed mutedly behind a glass-paneled wall.

The reason, he said, was simple:

“What will happen with almost complete certainty, is in December and January, our caucus-goers, the New Hampshire primary voters, will be evaluating who they think is the strongest general election candidate. They like all of us. I mean, that’s the truth. They like me. They like Hillary. And they like Obama. They are trying to decide who they think will be the strongest general election candidate. And that will get more intense, the closer we get to the caucus and primaries.”

Then came the sell:

“Well, this is not even close—who’s the strongest general election candidate. Every piece of empirical evidence shows you exactly the same thing that your gut will tell you anyway.”

To support his argument, he cited a poll that he said showed him outperforming Mrs. Clinton and Mr. Obama in head-to-head match-ups with leading Republican candidates.

“I saw a poll a week and a half ago, done by an independent polling firm, testing each of us against the top four Republicans, in about, I want to say, this isn’t going to be exactly right, but in about 20 states, mostly swing states,” Mr. Edwards said. “And I beat every Republican in 20 states. All of ‘em. Hillary won in about half the states roughly, close to half, and Obama, I think, won nowhere, if I remember correctly.”

(The Edwards campaign said it could not locate the independent poll that Mr. Edwards was referring to, but pointed to in-house polling from June that they said showed Mr. Edwards as the Democratic candidate with the most success against Republicans in match-ups nationally and in key battleground states.)

Mr. Edwards also argued that Democrats running for Congress in states like Montana and Georgia and Missouri would all much rather have Mr. Edwards at the top of the ticket.

“I’m telling you this is where this is going,” said Mr. Edwards. “And it is completely predictable.”

Mr. Edwards attributed his opponents’ lead in national polls to media coverage, and pleaded with his audience not to be swayed by their impressive fund-raising totals.

“It’s very important not to be deceived about what you see about a lot of national media attention and national Democratic primary voter polls, which are a direct reflection of whoever is getting publicity at that moment. That’s all they are,” Mr. Edwards said, adding that the only places voters actually had gotten to know the candidates were Iowa and New Hampshire, and to a lesser extent Nevada and South Carolina. “That’s just the reality of the way this works.”

And just as Mrs. Clinton often emphasizes what she calls her experience in the White House to demonstrate that she is the most prepared for the job, Mr. Edwards called on his own personal experience running for the White House to prove that he was the candidate who actually knew what it took to get there.

“In 2004 John Kerry won the nomination in Iowa,” he said. “I didn’t know it—painfully, I didn’t know it, since I finished second—but I thought it began a two-person race. What I didn’t understand is that there is such a wave of momentum behind the winner of the Iowa caucus that it is extraordinarily hard to turn it around.”

Mr. Edwards tried to convince his supporters and donors that despite his more modest fund-raising totals and his being behind in national surveys, his slight lead in Iowa polls put him in an enviable position.

“Just in case you don’t know, every campaign knows what I just said,” Mr. Edwards said about the difficulty of turning around after a defeat in Iowa. “This is not just me. If you want to know what people believe matters, look at where Obama and Hillary are spending their time and where they are spending their money. Follow the money and follow the candidates’ time and you will know what they think matters.”

He added that “both of them, by the way, have been in Iowa more than me in this campaign—they are living in Iowa and New Hampshire, because they understand that if you lose Iowa it is incredibly hard to turn it around.”

Mr. Edwards didn’t bring up the fact that he virtually took up residence in Iowa for months, if not years, before officially joining the race, helping him to build the small lead there that he still clings to over Mrs. Clinton in most polls.

“So this is what we are facing,” Mr. Edwards said. “We have to get past the emotion and the glitz and get to what matters.”