Through his extraordinary speech, which was full of an unusual number of criticisms from a former president, Obama also layered in his quintessential hope and calls for unity.
When Obama stood in front of the IL crowd on Friday and went after Trump by name, then called on young people to vote in November to "restore some semblance of sanity to our politics", Republicans felt like he was talking to their base too.
Here are the notable important things he said during the speech, including this helpful reminder about democracy: "This is not a rock concert". "I'm sorry, I watched it, but I fell asleep", the president said.
"Appealing to tribe, appealing to fear, pitting one group against another, telling people that order and security will be restored if it weren't for those who don't look like us or don't sound like us or don't pray like we do - that's an old playbook", he said. "He is a symptom, not the cause".
He addressed the student body of the University of IL, stating that they happened to be coming of age at a time when the backlash against American progress was overwhelming, and that most of said backlash spawned from those with power and privilege who wanted to maintain their status through polarization and division.
"None of this is conservative", Obama said.
Noting the history of former presidents avoiding the rough and tumble of politics, Mr Obama acknowledged his sharp critique of Mr Trump was something of a departure from tradition.
"There is a phrase that we used to use [when I was governor] for staff that acted this way, and it's called 'we know better, '" Paterson said.
Speaking to supporters at a fundraiser in Fargo, North Dakota, he dismissed Obama's speech.
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Obama has weighed in from time to time, mainly through written statements criticizing the reversal of his policies, and he made a few campaign appearances during off-year elections in 2017 taking issue with the president.
Obama also delivered a message via a NowThis video released Saturday urging young people to get out and vote.
Obama has maintained a low public profile since leaving office, but with midterm elections coming in November, he spoke Saturday at an Anaheim, California, rally in support of Democratic candidates in districts won by Democratic presidential candidate Hillary Clinton in 2016.
But, Mr Obama added, when there is a vacuum in democracy, "other voices fill the void".
Trump allies like Sen.
"The threat to our democracy doesn't just come from Donald Trump", Obama said. "The stakes really are higher. It is us not doing what we're supposed to do", he said.
"The truth is, the American people in 2016 rejected the policy and direction of Barack Obama when they elected President Donald Trump", he said.
If Democrats win control of one or both chambers in Congress in November, they would be able not just to stymie Trump's agenda but to launch investigations of the Trump administration.