Haha Now your headline makes you sound like a Keynesian, which we know you are not. But...

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The classic answer is that as long as the public debt is less than one year’s GDP, it is tolerable. Above that, the public debt is a problem. This year’s GDP will be in the $20.5 trillion range, meaning the debt far exceeds one year’s GDP.

Says who? where is your citation of proof that "above that the public debt is a problem"?

A quick bit of research as to who owns US debt:

32.5% US Investors (bond holders, etc)

11.2% Federal Reserve by buying US treasury bonds mostly

27.0% US Govt owns its own debt-mostly via Social Security and federal pension funds.

29.3% foreign investors- China and Japan mostly, but other entities such as Ireland, Brazil and UK

In other words, The federal govt owes 1/3rd of the debt to other AMERICANS as investments and another third to ITSELF.

Govt debt to itself is largely ledger column transfers.

Apparently rightwing politician and economists only worry about debt and deficits when a Democrat is in the White House. Remember Cheney blowing up the debt with illegal wars stating "deficits don't matter" and Trump blowing up the debt with a sugar hit tax cut bill that largely benefits the wealthy and corporations. In fact GWBush and Trump both blew up the deficit (and debt) with misguided tax cut bills after being handed decent economic conditions.

Republicans then whine about debt when the Democrats are in charge to stifle Democratic success. When they do cry about debt when in charge, Republicans use it to cut the safety net (unemployment, food stamps etc).