SILVER SPRING, Md. — His wife’s campaign may be foundering, but President Clinton is sticking with the soft sell.

In five appearances yesterday in Washington, D.C., and across Maryland, the name of Mrs. Clinton’s sole remaining Democratic opponent never crossed the former president’s lips.

With nary a mention of Senator Obama, Mr. Clinton talked up the former first lady all day, telling audiences of senior citizens and African-American churchgoers that Mrs. Clinton had “by far the most aggressive plans” on health care policy and the economy, and that she was candidate best prepared to make her campaign proposals “come alive.”

Democratic voters in Maryland, Washington, D.C., and Virginia, head to the polls tomorrow in what is being called the Potomac primary, in which more than 200 delegates are at stake.

The Clintons were out in force yesterday with Chelsea Clinton stumping in Maryland and the candidate herself appearing in Virginia and Maryland.

Mr. Clinton came closest to criticizing the Illinois senator in speaking at a Democratic club and before two retirement communities, suggesting that Mr. Obama was wasting a rare political consensus in favor of universal health care by offering a plan that would not cover every American.

The Clinton campaign and some policy experts say Mr. Obama’s health care plan would leave as many as 15 million Americans uninsured because it does not require adults to buy coverage.

“This is the biggest policy difference in this primary,” Mr. Clinton said at a Silver Spring retirement community. “The Democratic Party’s been waiting over 50 years for universal health coverage. Now we’ve got all the interest groups for it, and we’re going to walk away from it? Not if you vote for Hillary.”

The former president has dialed back his direct attacks on Mr. Obama after a perceived backlash in South Carolina, where Mr. Obama trounced Mrs. Clinton by 28 points. Mr. Clinton’s tone was even more measured as he addressed black churches in Washington and in Bowie, Md. He said he had waited his entire life to vote for both a woman and an African American for president, and he was rueful of having to choose between one or the other this year. “I wonder why God gave us this strange dilemma,” he mused. “I can’t answer that.”

Mr. Obama has received eight out of every 10 African American votes in several states, and, as Mr. Clinton spoke before more than 2,000 at the Temple of Praise in Washington, he seemed resigned to the fact that he was not going to win over a majority of the congregation, which gave him a standing ovation nonetheless.

“Pray about it, and think about it, and know that what ever you do, my family will be grateful for your blessings,” Mr. Clinton said. “Whatever you decide, we honor.” Several hundred more cheered him at a Methodist church in Bowie, but even as they applauded his 20-minute speech, one woman in a back pew could be heard saying, “He still won’t get my vote. He still won’t get my vote.”

Mr. Clinton stumped for his wife a day after Mr. Obama beat her by wide margins in Democratic caucuses in Nebraska and Washington state, and in a primary in Louisiana. Mrs. Clinton lost again to Mr. Obama in the Maine caucuses, where many had expected her to win.

With the exception of Nevada, Mr. Obama has dominated elections held by caucus, where voters have to state their preference at a designated time.

The Clinton campaign has repeatedly suggested that the process disenfranchises voters who can’t get off from work to vote, and the former president offered a blunt explanation for Mr. Obama’s success yesterday. “The caucuses tend to be dominated by upper income Democrats and younger people who have more free time,” he told the Battle Grove Democratic club in Dundalk, Md. “The people who work for a living need Hillary to be their president.”

At Mr. Clinton’s last stop, residents at the Leisure World retirement community in Silver Spring gave him an enthusiastic ovation. Betty Conway, 83, said she had been a Republican since the Eisenhower administration but that she voted for Mr. Clinton twice and was eagerly anticipating casting her ballot for Mrs. Clinton. “He’s too young,” she said of Mr. Obama. “He doesn’t have the experience.” She also confided that she was unsure if she was ready for an African-American president.

She left the event with a friend Elaine Sirkis, 77, who was pulled in the opposite direction. “I’m with Obama. I’m with the young people,” she said. Plus, she added: “I don’t know that I’m ready for a woman.”