Aamer Madhani

USA TODAY

CHICAGO — Three months after leaving the White House, former president Barack Obama stepped back into the spotlight Monday to encourage young people to become civically engaged while lamenting the increasing polarization of American politics.

And he did it without uttering the words: Donald Trump.

In his first post-presidency public appearance, Obama — while expressing concern that the current political environment is turning off Americans — notably managed to steer clear of critiquing President Trump and stick to the tradition of former presidents giving their predecessors space in the early days of an administration.

“What’s been going on while I’ve been gone?” joked Obama as he took the stage for a forum with Chicago students and young professionals to discuss ways to improve civic engagement.

New presidents — including Obama when he took office in 2009 following the George W. Bush presidency and in the midst of a deep recession — have grumbled over problems they’ve inherited from their predecessor but have aimed to avoid personalizing the criticism. Trump has tread into uncharted waters with his rhetoric about the Obama administration, analysts say.

In March, Trump lobbed unsubstantiated charges that Obama “wiretapped” him at Trump Tower during the presidential campaign. Earlier this month, the president suggested Obama’s national security adviser, Susan Rice, may have committed a crime by seeking to learn the identities of Trump associates swept up in surveillance of foreign officials by U.S. spy agencies.

There was bad blood between the two men for years ahead of Trump’s election over the 45th president’s claim that Obama was not born in the U.S. — an assertion that Trump walked away from in the midst of the 2016 campaign.

Since leaving office, Obama — who has taken vacations to the Caribbean, Palm Springs, Calif., and French Polynesia — has managed to avoid the spotlight and has mostly avoided weighing in on Trump, who has sought to undo Obama’s signature health care law, tighten immigration rules and roll back environmental regulations. In one notable exception, Obama offered a statement of support in late January for protesters who staged massive demonstrations at the nation’s airports in response to Trump’s travel order that impacted travelers and immigrants from several predominantly Muslim countries.

In the lead-up to Monday's forum, aides to the former president said Obama’s intent was to discuss issues with the students based on his own views and priorities that shaped his presidency. During the more than hour-long appearance, Obama spent most of the forum quizzing the young panelists about their ideas for getting fellow young Americans more engaged in politics and shaping policy.

He told the panelists, an audience of mostly college-age students, that he planned to dedicate much of his energy in the first chapter of his post-White House life to working with young people "to take up the baton and take their crack at changing the world."

"The one thing that I'm absolutely convinced of is that, yes we confront a whole range of challenges," said Obama, who noted issues such as climate change, lack of opportunity in some communities and needs for change in the U.S. justice system. "All those issues are serious and daunting, but they are not insoluble. What is preventing us from tackling them and making more progress really has to do with our politics and our civil life."

Obama’s public appearance came as Trump is closing in on the 100th day of his presidency, a milestone that will be marked without a major legislative victory and the 45th president’s approval ratings standing at 42%, according to a Washington Post/ABC News poll published Sunday. It marks the lowest approval rating at this point of a presidency since Dwight Eisenhower was in the White House.

While some of his backers are eager for Obama to weigh in on Trump’s presidency, Obama’s silence might be the most effective campaign tool for Democrats hoping to win Republican-held House seats in Georgia and Montana in upcoming special elections and as the party looks toward the 2018 midterm elections, said Susan MacManus, a political scientist at the University of South Florida.

“The way Obama managed his presidency compared to the current presidency is making some people who didn’t support him reconsider his presidency in a positive way,” MacManus said. “Speaking out during this quiet moment for Obama risks interrupting peoples’ reflections on his presidency that might be improving from where they were at when he left office.”

The former president chose the University of Chicago, where he served as a lecturer at the law school, to return to the spotlight. Obama also waited several weeks longer than his two most recent predecessors to deliver his first post-presidency remarks.

Bill Clinton spoke to a private conference sponsored by Wall Street investment company Morgan Stanley less than a month after leaving office. George W. Bush waited about two months to make his first post-presidential appearance in Calgary, and notably declined to critique the early days of Obama administration. Bush argued the then-new president “deserves my silence.”

Edward Frantz, a presidential and political historian at the University of Indianapolis, noted that Herbert Hoover and his successor Franklin D. Roosevelt battled over economic policy. And Theodore Roosevelt fiercely and publicly criticized his successor William Howard Taft after leaving office.

But the nature of the criticism that Trump has launched at Obama marks a unique moment in modern U.S. history, Frantz says.

“We are in unchartered waters,” Frantz said. “The closest you may have is Franklin Roosevelt with Herbert Hoover, but those were never personal attacks. Those were attacks against the Republican policies and maybe the Hoover administration’s economic policies but those were quite different indeed than attacking someone’s character and honesty.”

After three-month vacation, Obama to return to public eye

Frantz said that Obama, 55, is well aware that he likely has decades ahead to build his legacy and is thinking beyond the current polarizing moment in American politics.

“Dwight Eisenhower’s reputation and evaluation of what his presidency had been like improved dramatically in the years following his presidency,” Frantz said. “A lot of that had to do with the people who followed him. If Barack Obama, as former president, is able to maintain this serenity, his discipline of 'no drama' (that he forged) as president …. he has a real self-serving interest in making sure he’s deliberate in what he says now.”

Follow USA TODAY Chicago correspondent Aamer Madhani on Twitter: @AamerISmad