Indefinitely, with a caveat. Debt isn’t a requirement to maintain dominance. Recall not-so-long ago, the 1990s were characterized by decreasing government debt ultimately leading to a small surplus. At the same time, the US enjoyed a then record economic expansion.
The caveat is that Putin has installed a number of anti-American politicians who are busy disabling the institutions that made America a world leader in the first place. Due to this intense anti-American sentiment combined with extreme cowardice they may turn out to be successful.