His step back into the political arena offered a preview of his message for the fall's midterms.
Trump meanwhile said he fell asleep during the former president's speech, and said Democrats would have caused a negative GDP growth.
The Republican Party's refusal to compromise with Obama on health care, climate, deficit reduction, and so on was not because Obama treated them too arrogantly or refused to address the deficit seriously.
The speech will be an indictment of current events in the nation's capital, one Obama adviser said, and Obama will be "much more, much more pointed about what's at stake right now", and how "people need to take their responsibility seriously". Obama is likely to be less helpful in some of the most competitive Senate races playing out in states Trump won. "If I was the Republicans, I would be very nervous about this". John McCain, Obama delivered a speech seen as a jab at Trump. "In fact, the best explanation of President Trump's victory are the "results" of the Obama Presidency!"
Breitbart.com contributor Joel B. Pollak not only attacked Obama in a September 7 critique of the speech, but also, the University of IL itself.
Barack Obama has largely refrained from criticizing his successor, but he delivered his strongest rebuke yet on Friday in a speech at the University of IL.
Mr Trump told supporters in Montana yesterday that Republicans needed to maintain control of Congress to stave off possible impeachment proceedings against him, although Democrats have played down any discussion of that approach. All these terrified tea party activists, and the Republican leaders warning of profound social transformation, were really just concerned about the budget deficit. A series of former presidents have avoided critiquing their successors, and Obama has attempted to keep that tradition since he left office in January 2017.
"We're supposed to stand up to discrimination", Obama said.
"It's not conservative", Obama said. He will spend this Saturday in California stumping for seven congressional candidates at a Democratic Congressional Campaign Committee event and will head to OH next week to campaign for gubernatorial candidate Richard Cordray. "Doubling down on that strategy won't work in 2018 either".
Obama is re-entering the public eye two months before voters head to the polls for the midterm elections on November 6.