President Obama, during a conversation with the nation's governors on Monday, blamed the growing national debt on skyrocketing healthcare costs and a significant aging population in the country.

In the years since passage of the Affordable Care Act, Obama said the nation's spending on healthcare has "stabilized," but it is still growing over the long haul, something Washington still needs to fix once he's gone.

"The real problem when it comes to debt is very simple," Obama said in response to a question from Kentucky Gov. Matt Bevin about what he intends to do in his last months to raise awareness about the issue. "It is that our population is getting older and we use a lot of healthcare. We spend more, frankly, than most other advanced nations."

Roughly, the nation spends about 6-8 percent more than other advanced countries per capita on healthcare, he said.

"That difference is our debt and that is the reason why since I came into office I was interested in reforming healthcare. It was not just the compassion I felt for people personally being impacted ... It also had to do with the fact that this system is hugely inefficient, and if we don't make it more efficient than we're not going to solve our debt problem.

"What we're going to have to tackle, long term, is healthcare spending," Obama said. The president acknowledged that the politics around the Affordable Care Act had complicated efforts to have that conversation.

"My hope is that we get into a serious conversation," Obama said. "Maybe it'll have to happen once I'm gone."