Regardless whether this "debt" have to be paid or not, there's no doubt America is overreaching itself. Just look at all the constant war it initiated in the past years. Meanwhile other countries like China are slithering their way to the top. I'm not fond of the Chinese government as well but they surely are playing a good game right now and could be the center of a new system. I mean, the One Belt project would definitely make them the hegemon of their side of the globe (don't know how Russia would respond though).
If we look in national debt of the United States, compared with other countries, USA have Nr. 1 position with 19.907 USD billions national debt. See link here -
http://www.usdebtclock.org/world-debt-clock.html. What can do Trump with this ? Shortly - nothing, it is largest country debt in the world.
More important question is who is the owner of this national debt?
China, of course.
So, in a way, China have great to how to control America.
Until now, America could manage this big debt.
After all, if needed, they can simple print more money

In the long term, it's very difficult to say what will happen with this debt.
The problem is if countries start to say meh to the dollar standard.