It doesn't matter who is responsible for more of the National Debt. Quite a lot of it was bipartisan. Practically every elected official for generations has angled for their share of the pork.
What matter is if it is sustainable. For now, it is. I hope it lasts several more years. However, there are a few truths:
Tax revenues aren't enough to cover current spending, so we borrow more.
There is no excess tax revenues to repay principal. We are not paying down on principal, in fact we borrow more and cover interest payments by borrowing more.
The Federal Reserve doesn't dare raise interest rates much higher, as each increase raises what the U.S. government needs to pay in interest.
Social Security's "trust fund" is currently spending down, and older bonds are expiring, and portions are being reinvested at around 2% interest - pitiful interest. SSDI's "trust fund" is slated to run out this year (SSDI usage, which ends at age 65, has exploded to twice as many people in the past 15 years, though the number of Americans has only increased about 11% (and labor force participation is at 1980s lows), and Congress likely will want to piggy-back it on the larger Social Security "trust fund" in order not to raise taxes. Parts of Medicare's "trust fund" are slated to run out this year (the Federal "single payer" can't tame hospital and doctors' fees, nor negotiate for drug discounts with Big Pharma).
The Federal Reserve will continue to print using "Quantitative Easing", which in the current deflationary era won't likely cause much harm, but in the long term, could lead to problems as more oil is sold in other currencies than the dollar, and other countries resort to settling payments in yuan, euro, etc. Especially if you follow the ka-POW! theory (deflation, then inflation).