“Most of those states haven’t voted Democratic in a presidential since the Johnson landslide over Goldwater in 1964, and we don’t see that changing,” said Harold Ickes, a senior adviser to Mrs. Clinton. “They’re great states, but Idaho, Nebraska and the Carolinas are not going to be in the Democratic column in November. He’s winning the Democratic process, but that is virtually irrelevant to the general election.”

Look deeper, the Obama campaign contends, and there is another argument in his favor in traditionally non-Democratic states: He has drawn more votes from independents and Republicans than Mrs. Clinton has. But it is unclear whether independents and some Republicans in swing states or Republican-leaning states would choose him over Senator John McCain of Arizona, the presumptive Republican nominee.

At the same time, Mr. Obama has argued that Mrs. Clinton’s victories in closely contested states like Arizona, Nevada and Ohio were no slight against him. Yet he has not shown that he can win as much support from blue-collar workers and Hispanics as she has.

In conversations with superdelegates, Obama advisers have cast Mrs. Clinton as a divisive figure who would struggle to win swing states and be a drag on other Democratic candidates. That argument has yet to be proved at the ballot box, though some political analysts and state officials say that they believe Mrs. Clinton could wound the ticket in some states, because polls have shown her to be a polarizing figure.

“Some state polls that I’ve seen show Obama doing much better against McCain than Hillary; that’s a legitimate cause for concern for state officials who are superdelegates,” said Steve Murphy, a Democratic strategist who is not working for either candidate. “In the last few cycles, the Democratic vote for the House of Representatives has aligned closely with the percentage of the vote we received in the presidential race.”

Mrs. Clinton points to her victories in the Texas primary and in Arkansas and Tennessee as a sign that she has appeal in states that Democrats struggle to carry in a general election.

What is more, Clinton advisers question whether Mr. Obama has a real base of support in the swing states Mrs. Clinton won, arguing that he has relied on upper-income liberals, college-educated voters and students, groups that, the Clinton team argues, will support any Democratic nominee. That said, many of these voters have appeared far more passionate about Mr. Obama than Mrs. Clinton.