Wrong
It doesn't have everything to do with it, but it does have a great deal to do with it
Second, the U.S. Has to honor its obligations. Or lose every bit of the influence and power that it has and you are so worried about. The worst thing any administration could do is not pay the bills, especially default on the debt.
That means that each admin is responsible for the sins of all of the previous, and there were plenty on each side.
The snowball effect is in play too.
Serious stuff and it don't fit on on a bumper sticker and the only answer is drastic cuts, including to programs that you like, and raising taxes on the middle class. Taxing the rich doesn't raise enough and cuttimg taxes does not, or at least never has, increased tax revenues enough to cover the spread.
They are both lying through their teeth, and they are both proposing gimmickry and fairy tales.
You might be one of the few people actually willing to endure the pain necessary to eliminate the deficit and pay down the debt, but that is statistically unlikely.