Debt-cutting measures need to be a consideration for President-elect Donald Trump, as he prepares to execute on campaign promises to boost infrastructure spending, rebuild the military and slash taxes, according to the bipartisan co-chairs of the Campaign to Fix the Debt.



Trump policies, without red ink-reducing components, "[by] our estimate would explode the debt by $5 trillion in the first 10 years ... and by the end of 10 years our debt as percentage of GDP would be over 100 percent," Democratic former Pennsylvania Gov. Ed Rendell told CNBC's "Squawk Box" on Tuesday.



There are ways for Trump to reduce the national debt of nearly $20 trillion while still pursuing his policy agenda, said Judd Gregg, Republican former New Hampshire senator and governor and Rendell's co-chair at Fix the Debt.



"We put together a Simpson-Bowles 2.0 plan, which is sort of a comprehensive proposal, and we've also set up a cafeteria line of ideas on how you can address things like tax reform, which is absolutely critical. It should be one of the first things out of the box," Gregg said.



"I think tax reform would create massive economic activity, which would actually help us significantly out of our debt problems," he said, while predicting that it's possible for the U.S. economy to once again grow at a 4 percent rate, after being stalled since the 2008 financial crisis.



The reference to Simpson-Bowles was a nod to the 2010 debt-reduction plan that never got off the ground. It was crafted by Republican Alan Simpson and Democrat Erskine Bowles, co-chairs of President Barack Obama's debt commission.



Bowles, White House chief of staff under President Bill Clinton, and former Wyoming Senator Simpson in 2012 founded the Campaign to Fix the Debt.

