That's, um, not how the economy works. You don't "own" the U.S. if you buy U.S. Government debt. You own a claim against future taxing or money-printing authority in the U.S. which is a very different thing.
While excessive spending could yield inflationary pressure in the future, keep in mind that government spending in the U.S. represents about 30% of GDP, of which about 20% is Federal and the remainder is state and local. We're running deficits now, although they have been shrinking since the impact of the last round of tax cuts has washed through the economy.
By way of comparison, public sector spending in France is over 50%.
Our national debt, by comparison, is about 65% of GDP. Germany runs 68%, France 68%, and the UK, about 40%.
The Wikipedia entry has a nice chart of its trend of the historical values. In the "modern" era (income tax), it's been as high as 120% (WWII) and as low as about 38% - during late 1970s / early 1980s stagflation.
You can see on the chart that it varied between about 60% and 65% through the 1990s, with a dip around 1999 / 2000 and then a spike thereafter coincident with the recession triggered by the tech. collapse.
cdg