Milwaukee, Wisconsin (CNN) - Despite a strained voice and a hectic campaign schedule, President Obama's rhetoric was as lofty as ever when he took the stage before 20,000 supporters here Saturday afternoon. Promising to be a voice in Washington, D.C. for voiceless Americans, the president told the crowd that those who listened closely to his speeches in 2008 should remember that "change we believe in is not just changing the president." -- Follow the Ticker on Twitter: @PoliticalTicker "It's changing our politics," he said. "It's changing the system. I ran because the voices of the American people, your voices had been shut out of our democracy for way too long." Using his message from 2008 to push back against Mitt Romney's claim that he's the true change candidate in this race, Obama said he's not done fighting for the change he promised four years ago. "Kids dreaming of becoming scientists or doctors, engineers or entrepreneurs, diplomats, maybe a president they need a champion, because the future will never have lobbyists like the status quo does," the president said, exciting the crowd. "But the dreams of those kids will be our saving grace. That's what we're fighting for. That's what this election's about. That's why I need you." At a time when fights in Washington are far from popular, Obama said that some fights are "fights that need to be had." And foreshadowing his approach to a budget showdown that looms over whichever candidate wins on Tuesday, the president pledged that