Donald Trump suggested that as president he would finance Social Security by requiring countries that benefit from U.S. military protection to pay for the service.

"We're the policeman of the world: We take care of Germany; we take care of Saudi Arabia; we take care of South Korea," he said during Thursday night's presidential debate. "Saudi Arabia was making a billion dollars a day and we were getting virtually nothing to protect them. ... We are going to be in a different world. We're going to negotiate real deals, now, and we're going to bring the wealth back to our country."

Trump offered that plan as a way to avoid Social Security's impending insolvency — the program runs out of money in 22 years — after initially promising to stabilize the program by eliminating "waste, fraud, and abuse." That position contrasted with Fla. Sen. Marco Rubio, who has proposed a politically-risky Social Security overhaul.

Rubio wants to raise the retirement age to 68 years old for people of his generation and raise it to 70 years old for people who are currently children, while leaving the age alone for current retirees and people close to retirement.

"If you do not do it, we will have a debt crisis, not to mention a crisis of Social Security and medicare," Rubio said. "Both parties have taken far too long to deal with it. It is one of the major issues confronting America. It's barely been asked in any of these debates and we'd better deal with it or we're going to have to explain to our children why they inherited this disaster."

Trump seemed to concur with Rubio in criticizing Democrats for refusing to cut Social Security, but pledged that he would also leave the program alone.

"The Democrats are doing nothing with Social Security, they're leaving it the way it is — in fact they want to increase it, they want to actually give more — and that's what we're up against," he said. "I will do everything within my power not to touch Social Security, to leave it the way it is, to make this country rich again, to bring back our jobs, to get rid of deficits, to get rid of waste, fraud, and abuse, which is rampant in this country, rampant, totally rampant. And it's my absolute intention to leave Social Security the way it is, not increase the age, and to leave it as is."

When CNN's Dana Bash noted that eliminating "improper payments" would only save $3 billion (out of an estimated $150 billion shortfall), Trump turned to the military option. He also suggested that the Social Security program's financial problems are somewhat less urgent than Rubio thinks. "You have 22 years," Trump said. "You have a long time to go. It's not long in terms of what we're talking about but it's a long time to go."