By Ayesha Rascoe and James Oliphant
PHILADELPHIA/DES MOINES, Iowa (Reuters) - With Hillary Clinton sidelined by pneumonia, President Barack Obama took up the Democrats' fight against Donald Trump on Tuesday, trying to quash the Republican presidential candidate's bid to appeal to working-class voters.
Obama, whose 50 percent job approval rating could help improve the climate for the Democratic ticket in the Nov. 8 election, rallied party faithful against Trump, the 70-year-old New York real estate developer, at an outdoor event in Philadelphia.
"This is a guy who spent 70 years on this earth showing no concern for working people. He spent most of his life trying to stay far away from working people. He wasn't going to let you on his golf course," Obama said.
Obama's campaign appearance was his first as a solo act on behalf of Clinton as he tries to ensure Democrats retain control of the White House once his eight years are over in January.
The president lauded new census numbers on income growth as proof that his administration's policies have helped improve the economy, an attempt to undermine Trump's argument that economic woes are deep.
"By so many measures, America is stronger and more prosperous than when we started out on this journey together," Obama said.
Clinton, who was Obama's secretary of state during his first term, rested at her home in the New York City suburb of Chappaqua, from pneumonia. She was diagnosed with pneumonia on Friday but she kept it secret until she nearly collapsed in on Sunday at a ceremony in Manhattan marking the Sept. 11, 2001, attacks.
At a rally in Des Moines, Trump steered clear of mentioning her illness but stepped up efforts to wring maximum advantage from Clinton’s controversial comment that his supporters are “deplorables."
"While my opponent slanders you as deplorable and irredeemable, I call you hardworking American patriots who love your country and want a better future for all of our people," said Trump, who tried to portray the former first lady as out of touch with ordinary Americans.
Clinton said in a speech last week that half of Trump's supporters belong "in a basket of deplorables" and accused them of being racist and homophobic. She later said she regretted the remark.
Trump, who has often bragged about his wealth, has come under fire himself for rhetoric against minorities during his campaign, including describing Mexican immigrants as criminals and rapists, suggesting that a judge could not be fair because of his Mexican-American heritage, and proposing a temporary ban on Muslim immigration to the United States.
After struggling in opinion polls in August, Trump has erased most of Clinton's lead in national surveys and is competitive again in many battleground states where the White House race is likely to be decided.
Trump's vice presidential running mate, Indiana Governor Mike Pence, used Clinton's comment to try to build more unity among Republicans, appearing at a news conference with Paul Ryan, the speaker of the House of Representatives and the top U.S. elected Republican.
"I think millions of Americans were shocked and saddened to see Hillary Clinton refer to people across this country as a basket of deplorables in a prepared speech before wealthy donors in New York City on Friday night," Pence said.
The "deplorables" comment featured at a Trump rally in Asheville, North Carolina, on Monday night that saw a resumption of some of the violence that disrupted his events earlier this year.
"Never in history has a major party presidential candidate so viciously demonized the American voter," Trump told the crowd.
Five people, including a minor, were arrested at the rally and charged with crimes including second degree trespassing and fighting in public, Asheville police said.
A man grabbed an anti-Trump protester's neck and punched him during the rally, video from NBC and ABC showed. Police said they also obtained an arrest warrant for the suspect in that incident.
Clinton is expected to return to the campaign trail later this week.
Trump will propose in a speech on Tuesday night allowing families to deduct the cost of childcare expenses from income taxes, his campaign said, a move aimed at bolstering his support among women voters.
It was formulated with the aid of Trump's daughter Ivanka Trump, an influential voice in his campaign.
(Additional reporting by Emily Stephenson, Eric Walsh and Jeff Mason in Washington and Laila Kearney in New York; Writing by Steve Holland and Susan Heavey; Editing by Alistair Bell and Leslie Adler)