PALO ALTO (CBS SF) – Making his case to a young audience at Facebook headquarters, President Barack Obama said trimming $4 trillion from the nation’s deficits over the next 12 years sounds like a lot but can be done.

Obama was in Palo Alto on Wednesday answering questions in person and online during a town hall at the home base of the popular social networking site.

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Most of those who attended in person were Facebook employees, and Obama noted the young demographic he was addressing and the novelty of a president holding a town hall meeting online.

“More people, especially young people, are getting their information through different media,” he said. “And obviously what all of you have done together is revolutionize how people get their information, how they process information, how they’re connected with each other.”

Obama spoke about the nation’s massive debt and ways to reduce the deficit, including by cutting health care costs, slashing defense spending and reducing tax breaks for the wealthiest Americans.

The president pointed out that that income group includes people like himself and Facebook founder Mark Zuckerberg, who moderated the event and was sitting next to him.

“I’m cool with that,” Zuckerberg said.

“I know you’re OK with that,” the president replied.

Obama recalled that in 2000, the country not only had a balanced budget, but a surplus as well, because both political parties made it their goal to spend wisely.

“Then we went through 10 years where we forgot what had created the surplus in the first place,” the president said. “So we had a massive tax cut that wasn’t offset by cuts in spending. We had two wars that weren’t paid for. We had a huge prescription drug plan that wasn’t paid for. By the time I started in office, we had a $1 trillion annual deficit.”

He said interest payments further added to the massive debt that had accumulated, and later on the recession, which added another $1 trillion. Now, the baby boomer generation is retiring at a greater rate and placing greater demand, especially on health care costs, Obama said.

“You put that all together and we have an unsustainable situation,” he said. “So right now we face a critical time where we’re going to have to make some decisions.”

Obama aims to reduce the deficit by a cumulative $4 trillion over roughly the next decade, and said about half of that would come from cuts in spending.

“I know that sounds like a lot of money. It is, but it’s doable if we do it in a balanced way.”

He said it is possible to make spending cuts selectively without hurting key areas like education, infrastructure and technology, which he said are crucial to the nation’s future.

Obama opposes the 2012 budget plan proposed by U.S. Rep. Paul Ryan, which some have called radical while others have said it is bold and courageous.

He said the plan was radical in that it essentially further reduces taxes for the wealthy and for corporations, and calls for cuts from the energy, education and transportation budgets.

“I guess you could call that bold. I would call it short sighted,” Obama said.

The president spoke extensively about education, saying that the system needs money and reform.

“It’s not an ‘either-or’ proposition, it’s a ‘both-and’ proposition,” he said.

He talked about the progress of the administration’s “Race to the Top” initiative, which gives school districts an opportunity to compete for federal funding by demonstrating a plan to improve their schools.

He promoted also the importance of the Science, Technology, Engineering and Math initiative, and said the improvement of education depends upon recruiting and compensating the brightest teachers, and assessing those teachers to ensure they are performing.

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The president said the slow housing market is a “real drag” on the economy, putting strain especially on first-time homebuyers. He said one way the government has addressed that problem is by establishing programs where those homebuyers can renegotiate the terms of their mortgage with their lenders.

“Frankly we’ve got to understand the days where it was really easy to buy a house without any money down is probably over,” Obama said.

Obama discussed his administration’s stance on immigration policy, conceding that it is a difficult issue, and shared his ideas for reform.

He said the legal immigration system should be more efficient so that there are not huge backlogs. Most Americans approve of immigration, but also want it to be done in an orderly process, the president said.

High-skilled immigrants who come to America and study should be able to stay if they want to reinvest in the country, Obama said.

“If we have smart people who want to come here and start businesses and are Ph.D.s in math and science and computer science, why don’t we want them to stay?” Obama said, inspiring loud applause. “Those are the job generators.”

He said there should be a way for unskilled workers who are lurking in the shadows out of fear for themselves and their families to also be legalized. He added that even so, they should be punished with a fine and required to learn English and pay their dues in other ways.

The president ended the meeting by saying that there is still a lot of work to do, but that the American people would have to move forward with optimism.

“Just remember that we’ve been through tougher times before and we’ve always come out on top,” he said. “If we come together we can solve all these problems. I can’t do it all by myself.”

Obama, who already has a lot of Facebook fans—more than 19 million on his official page—also took questions at the start of a West Coast trip aimed at building support for his deficit-reduction plans and raising money for his re-election bid.

Protesters gather at San Jose City Hall, April 20, 2011. (KCBS)

Protesters gather at San Jose City Hall, April 20, 2011. (KCBS)

President Obama touched down at SFO shortly before 1pm. He shook hands with a small crowd before taking off aboard Marine One on his way to Palo Alto, where he was greeted by a vocal group of protesters.

The president’s three-day trip is his most extensive travel since he announced his 2012 bid earlier this month.

That campaign could set new fundraising records as Obama courts high-dollar donors as well as young people, many of whom were among the small donors who buoyed his 2008 campaign.

In the evening, the President headed to Masonic Auditorium in San Francisco for a fundraising event that’s expected to draw thousands of people. He also attended a private dinner with dozens of supporters in the city’s Pacific Heights neighborhood.

Weeks of heated debate in Washington over long- and short-term spending have left Obama with some of the lowest approval ratings of his presidency, inculding a CBS 5 poll Wednesday that revealed 50 percent disapproval in California. But the numbers are even lower for the Republican-led House and Obama’s potential Republican challengers.

Voters said they want Washington to tackle deep deficit reductions, and both parties are responding—Obama with his plan to cut $4 trillion, and House Republicans with a plan they passed last week that seeks to cut $5.8 trillion in spending over 10 years. The challenge for the president and his Republican rivals is to also connect their efforts with the public’s pressing concerns over persistently high unemployment and rising gasoline prices.

Obama is using all of the resources at his disposal to make his case, from the town halls he’s holding this week to the interviews he conducted Monday with local television stations in politically important states. GOP lawmakers, too, are making use of the spring break on Capitol Hill to meet with constituents.

KCBS’ Doug Sovern Reports:

On Thursday, 100 of Obama’s backers plan to attend a private breakfast with him at the Saint Regis Hotel in San Francisco. He then heads to Los Angeles and Reno.

The president is due back in Washington on Friday.

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