Barack Obama celebrates the life and legacy of Nelson Mandela in Johannesburg on Tuesday, marking the centennial of the South African leader's birth.
It's one of Obama's most high-profile appearances since leaving the White House 18 months ago and a preview of what could be an active campaign schedule for the former president before the midterm elections this fall.
Tuesday's speech is not overtly political. But Mandela was the inspiration for Obama's first foray into politics — a protest against apartheid. And he sees important lessons for our own time in Mandela's perseverance and vision.
"The day he was released from prison gave me a sense of what human beings can do when they're guided by their hopes and not by their fears," Obama said in 2013, when Mandela died. "Like so many around the globe, I cannot fully imagine my own life without the example that Nelson Mandela set, and so long as I live I will do what I can to learn from him."
Aides say Obama's speech will be global in scope and focus on trends in human rights and tolerance. Not all of those trends are positive.
"In the U.S. and around the world, many see recent developments that run counter to Mandela's legacy," Obama adviser Ben Rhodes told The Associated Press. But Mandela's journey — from spending 27 years in prison to becoming the leader of a free South Africa — also offers a case study in persistence.
"We have been through darker times before and we can overcome these challenges to keep Mandela's vision alive," Rhodes said.
Obama has generally kept a low profile since leaving office and has avoided criticizing his successor directly. But on rare occasions, the former president has spoken up in defense of inclusive democratic values.
Last year, Obama told a large crowd near the Brandenburg Gate in Germany that in a modern, interconnected world, "we can't isolate ourselves. We can't hide behind a wall."
It was an implicit rebuke of President Trump's "America First" policies, delivered at a moment when Trump was scolding NATO allies for what he saw as inadequate defense spending — something Trump did again last week.
Obama also defended the global economic order, saying it had delivered unparalleled peace and prosperity. But he acknowledged that order was under attack.
"It has to be continually renewed, because there is a competing narrative of fear and xenophobia and nationalism and intolerance," Obama said. "We have to push back against those trends."
Last week, Trump told reporters in the U.K. that immigration is changing the culture of Europe in a negative way.
"I know it's politically not necessarily correct to say that, but I'll say it and I'll say it loud," Trump said.
Obama's critiques of Trump and his party are likely to grow more frequent this fall, when the former president is expected to campaign actively for Democratic House and Senate candidates.
But Obama is also looking beyond the United States and the next election.
When he traveled as president, Obama often made it a point to meet with young people who might form the next generation of leaders, and he'll do so again this week in South Africa. He's hosting a town hall in Johannesburg on Wednesday for 200 rising African leaders.