Hillary Clinton and Donald Trump mostly danced around questions on how to reduce the national debt, as Clinton reasserted a pledge not to add a penny to the debt, and Trump promised massive economic growth to lower the debt.

"I pay for everything I'm proposing," Clinton said when asked why her economic plan doesn't address the nearly $20 trillion national debt. "I do not add a penny to the national debt," she added, referring to the current upward trajectory of the nation's red ink.

To pay for new government spending programs, she said, "I've made it very clear: we are going where the money is. We are going to ask the wealthy and corporations to pay their fair share."

In the same segment, moderator Chris Wallace asked Trump about analyses from conservative economists finding that his plans would add to the debt, a line of criticism that Clinton had also raised throughout the debate.

As he has throughout the campaign and had earlier during the night, Trump responded that he would usher in extremely aggressive economic growth by renegotiating trade deals.

"I think you can go to five, six percent," he said, referring presumably to inflation-adjusted economic output growth. "And if we do, you don't have to bother asking the question" about the debt. Most economists believe that that rate of growth, which has been reached in the past, is not achievable given the country's demographics.

Asked later if he would consider a "grand bargain" on spending and taxes, Trump responded that he would be cutting taxes and repealing Obamacare, and said those changes to reduce the debt by creating new economic growth.

Asked the same question, Clinton also declined to say she would embrace such a deal, and instead said she would raise Social Security payroll taxes to pay for greater benefits for low-income workers and widows.

Neither candidate has proposed a plan to lower the federal debt. Instead, each has promised that they would not add to the debt with their fiscal plans any faster than is currently anticipated.

Yet the tax and spending plans that both candidates have outlined on the campaign trail would add to the deficit, according to outside nonpartisan analyses. Trump's campaign, in particular, has not convincingly defended its claim that his $6 trillion tax cut would be offset by other policies so that it doesn't add to the debt. And Clinton's called-for tax hikes would fall at least a few hundred billion dollars short of covering the spending programs she has outlined, in part because they would crimp economic growth. During Wednesday's debate Clinton claimed that there was "no evidence whatsoever" that higher tax rates would diminish growth.

In the 2012 presidential election, the candidates debated ways to reform entitlements and address the debt. President Obama campaigned on a $4 trillion deficit-reduction package, while Mitt Romney embraced medicare reform along the lines of Paul Ryan's proposals.

Then, the public debt held by the public was just above 70 percent of U.S. gross domestic product. Today, it has risen to 76 percent, and is expected to rise to 86 percent by the end of the decade and more thereafter, as projected by the Congressional Budget Office.

By the same agency's estimates, however, the long-term budget picture has become less dire in the intervening years, thanks to lower interest rates and falling Medicare costs. Nevertheless, it still warns that, without fiscal reform, the country faces potential problems down the road, including the possibility of a fiscal crisis.