Peter Peterson, the legendary co-founder of private equity firm Blackstone, says President Obama should be careful not to adopt too ambitious an agenda.

Peterson has written a new book, “The Education of an American Dreamer: How a Son of Greek Immigrants Learned His Way from a Nebraska Diner to Washington, Wall Street, and Beyond.”

He tells Moneynews that his major concern now, and the impetus for the book, is that he fears his kids and grandkids will not have the same opportunities to succeed as he did, if things continue on their current course.

Spending now risks an even bigger explosion of our debt burden, the Nixon administration Commerce Secretary tells Moneynews.

“I would say to him (Obama): be careful about trying to do too much too soon at too big an expense,” he says.

“We’re looking now at something approaching $2 trillion of deficits. We’re terribly dependent on foreign capital.”

“I would urge him to go a bit slower,” Peterson says.

“On healthcare, which he’s absolutely correct is the biggest problem that is confronted, talk about identifying the cost savings … upfront. If we don’t do that, we’re likely to get the costs but not the savings.”

Such a scenario “will add even further to the horrific deficit we’re now facing, and debts,” he says.

“By 2020 it looks as though our country’s debt will be about $20 trillion. That doesn’t even count the $45 trillion of unfunded promises we’ve made on future Social Security, Medicare and so forth.”

Peterson says a Chinese official recently told him, “Where are you going to get the money to fund those deficits? … Are you assuming that we’re going to lend you $2 trillion when we already have $1.5 trillion?”

In addition, the Chinese official said, “Do you really think it’s reasonable to think that you’re going to get all that money without raising your interest rates dramatically?”

In a larger sense, the problem is that we’ve become a country that’s got an aggravated case of short-termism, Peterson says.

“We’ve gone from being one of the big savers in the world to the poorest saver in the developed world. Yet we want to be big consumers. We’ve got in the habit of consuming more than we produce and borrowing the rest from abroad.”

That leaves us open to “the most likely next crisis … that foreigners will decide at some point that America’s fiscal house isn’t in order, and it’s too high a risk to keep lending us money.”

And what’s the implication of that?

“If they don’t lend us money, and we continue on these huge debts and deficits, we then run into this serious problem of where will we get the money to fund them, and what will we have to pay in interest rates to talk people into lending us money?” Peterson says.

“That will start a new crisis that I think it’s desperately important that we avoid.”

Peterson says he’s worried about his children and grandchildren.

“I’m very concerned about whether the American dream is going to be there for them.”