(Updated 4:35 p.m. ET)
(CBS News) President Barack Obama officially launched his reelection bid Saturday, drawing a sharp contrast between his vision and his challenger's, presumptive Republican nominee Mitt Romney.
"We're not going back.... We're going forward," the president said to a fiery crowd at Ohio State University in Columbus.
Repeatedly using his new campaign slogan "Forward," the president suggested that a Romney presidency would reverse Mr. Obama's policies benefiting the middle class and, instead, "rubber stamp" the congressional Republicans' agenda, reviving ideas of deregulation and trickle-down-economics that would benefit the wealthy.
"This is a make-or-break moment for the middle class, and we've been through too much to turn back."
Romney, the president said, believes "the same bad ideas will lead to a different result . . . or they're just hoping you won't remember the last time we tried it their way."
"Ohio, I'm here to say, 'We were there, we remember, and we are not going back. We are moving this country forward,'" the president said in his first of two campaign rallies Saturday marking the official kickoff off his campaign. (Watch President Obama's speech in video player.)
Subtly acknowledging that economic challenges remain, President Obama said, "It's not just about how we're doing today, but about how we're doing tomorrow."
During First Lady Michelle Obama's introduction of her husband, she spoke of her prided himself on paying for a small portion of her college education. She talked about Mr. Obama's mother and grandmother, who "like so many women, hit that glass ceiling."
Mrs. Obama reminded college students to register to vote because the president "needs your help."
"Get that done," she said.
During his 40-minute speech, Mr. Obama referenced political fights that raged during the Republican primary over women's health, again insisting a Romney presidency would be "turning back the clock."
"We don't need another political fight about women's right to choose or ending Planned Parenthood," the president said. "I want women to control their own health choices."
In addition to reaching out to women, the president referenced key voting blocs. He pushed for the DREAM Act, which would give a pathway to citizenship for children of undocumented immigrants. He hailed the repeal of "Don't Ask, Don't Tell," allowing gay service members to serve openly.
"We have come too far to abandon the change we fought for these past four years." Mr. Obama said. "And that's why I'm running for a second term as president of the United States."
At times, the crowd broke out into chants of "Four more years."
The president did not spend much time on foreign policy, but he noted the death of al Qaeda leader Osama bin Laden and that "for the first time in nine years, there are no Americans are fighting in Iraq."
He chided Romney for saying he would not announce a timeline for a troop withdrawal from Afghanistan. "I have. And I intend to keep it," Mr. Obama said.
The Romney campaign said the president's rhetoric doesn't meet reality.
"No matter how many lofty campaign speeches President Obama gives, the fact remains that American families are struggling on his watch: to pay their bills, find a job and keep their homes," spokesperson Andrea Saul wrote in a statement. "This November, they will hold him accountable for his broken promises and ineffective leadership."
Ohio Senator Rob Portman, who has been mentioned as a possible Romney vice presidential choice, pushed back against the president who spoke in his home state. In an op-ed on Fox News' website, Portman said Americans are "hurting" and "worried" about their economic security.
Portman added: "Four years ago, the country had high hopes for President-elect Barack Obama. But now the president has to run on his record. And he will have to explain to the American people why his vision for bigger government, more spending, and higher taxes will work over the next four years when it hasn't worked in the past three and a half years."
Six months ahead of Election Day, the race is close.in key battleground states of Ohio and Florida. In Virginia, however, Mr. Obama is leading Romney 51-44 percent, in a .
"Ohio, this election will be even closer than the last," the president predicted, but asked the audience to work "even harder" than in 2008.
Mr. Obama added: "If you're willing to stick with me, if you're willing to fight with me, and press on with me, if you're willing to work even harder in this election than you did in the last election, I guarantee you we will move this country forward. We will finish what we started."