"Why are we not hearing from him? We've got to hear from him," said Sarah Kovner, a New York City Democratic activist who raised more than $1 million for Mr. Obama's campaigns. "Democrats are desperate."
"Everything that Trump is doing really requires a response," Ms. Kovner added.
Mr. Obama and a small cadre of former White House aides in his Washington office know that anything he says in public, no matter how veiled, will be interpreted as criticism of Mr. Trump.
Mr. Obama's aides say he will also not criticize Mr. Trump in his private paid speeches. The aides would not say how much Mr. Obama will be paid per speech, but former President Bill Clinton averaged more than $200,000 per speech between 2001 and 2015; former President George W. Bush is reportedly paid $100,000 to $175,000 for each appearance.
Aides have rejected the idea that Mr. Obama should actively wage a public feud against Mr. Trump, with whom he has not spoken since the inauguration. They believe that such a fight would give the current president the high-profile political foil he wants to further energize his conservative supporters.
Mr. Obama has also concluded that his voice is not essential in the daily back-and-forth. His aides note that a new level of civic activism among Democrats eager to challenge Mr. Trump has emerged without much encouragement from the former leader of the Democratic Party. And many of Mr. Trump's attacks on Obama-era policies - like the Affordable Care Act - have so far failed or stalled.
Instead, Mr. Obama is preparing remarks that focus on broader themes he hopes will keep him above the cable-television combat and the Capitol Hill debates: civic engagement, the health of the planet, the need for diplomacy, civil rights and the development of a new generation of young American leaders.
"Trump becomes a distraction from what he wants to do," said Kevin Lewis, a spokesman for Mr. Obama.
Mr. Obama is not the first president to try to avoid the political fights that consumed his time in office. Mr. Bush resisted pressure from his aides and supporters to criticize his successor during the months after Mr. Obama took office.
"People around him wanted him to do it," recalled James Glassman, the founding director of the George W. Bush Institute. "People would come to me and say, 'Can't you get the president to defend No Child Left Behind?' His legacy was about to be wiped off the face of the earth. The answer was no. That's not the way he saw his post-presidency."
Mr. Glassman said that Mr. Bush's keep-quiet approach toward Mr. Obama was shaped by what he saw as unfair criticism by former President Jimmy Carter of his father, the elder President George Bush.
"I would try to get him to do things like talk about immigration policy and say the things he said as president," Mr. Glassman said of Mr. Bush. "He would absolutely not do it."
But rarely has an outgoing president faced a successor like Mr. Trump.
In the weeks after winning the White House, Mr. Trump assembled a cabinet intended to eradicate most of Mr. Obama's accomplishments. Once in office, Mr. Trump accused the former president of wiretapping him, without offering any evidence, and he said on Twitter that Mr. Obama was a " Bad (or sick) guy! " Mr. Trump also accused his predecessor of being behind national security leaks, and he all but blamed Mr. Obama for Syria's chemical weapons attacks.
The pressure on Mr. Obama to enter the fray has steadily increased as Mr. Trump moved to reverse Obama-era environmental protections, ban travel from several predominantly Muslim countries, abandon trade deals, eliminate progressive regulations and install a conservative Supreme Court justice.
Through it all, Mr. Obama has stayed mostly silent. (During a conference call with thousands of despairing supporters a week after the election, Mr. Obama said only: "Don't mope. And don't get complacent.")
After the Obama family moved into a nine-bedroom mansion a few miles from the White House in January, they began a series of vacations, each captured in grainy snapshots posted online.
Mr. Obama quickly left Washington for Palm Springs, Calif., and then it was off to a private island in the British Virgin Islands with the British billionaire Richard Branson, where he was photographed kitesurfing.
More recently, Mr. Obama and his wife, Michelle, spent nearly a month in French Polynesia. A snapshot of the former president taking a picture of Michelle on the deck of Mr. Geffen's yacht, the Rising Sun, went viral on the internet.
On Monday, the former president will return to his adopted hometown, Chicago, for a conversation with a half-dozen young people and a question-and-answer session with an audience of college students.
As he begins his paid speeches, Mr. Obama, who is represented by the Harry Walker Agency, is scheduled to engage in a private conversation with the historian Doris Kearns Goodwin for the employees of the A&E television network.
On May 7 in Boston, Mr. Obama will accept the Profile in Courage Award given annually by the John F. Kennedy Library Foundation. He will deliver a speech at the library's black-tie dinner. His remarks - built around the theme of what courage means in today's world - will not name Mr. Trump.
Later in May, Mr. Obama will travel with his White House chef and friend, Sam Kass, to Italy for a speech at the Global Food Innovation Summit about the effect of climate change on food sources. On May 25, Mr. Obama is to deliver a speech at the Brandenburg Gate in Berlin, joined by Ms. Merkel, a close ally during his time in office.
In both European cities, Mr. Obama will also deliver paid speeches.
Some longtime supporters still hope to see Mr. Obama eventually return to the impassioned oratory they remember from the 2008 and 2012 campaign trail.
"Everyone is anxious," said John Morgan, a lawyer and one of Mr. Obama's longtime donors.
But Mr. Morgan said it made more sense for Mr. Obama to keep a low profile until next year, when Democratic candidates for the House and Senate will need help winning re-election.
"You have got to pick your battles. Timing is everything," Mr. Morgan said. "If you come out 100 days after the election throwing haymakers, I think your credibility wanes. He's better to save himself for the fall of 2018 and speak from a higher perch."
Louis Frillman, a board member of Organizing for Action, the group that grew out of Mr. Obama's campaign, said Democrats needed to learn not to rely only on the former president. But he said it would be up to Mr. Obama to decide how much to engage.
"I'm not going to give him public advice," Mr. Frillman said. "He'll know how to deal with things in due course."