The US is making lots of steps typical of falling empires. This includes blind belief in the strength of its currency. Even big investors are starting to get worried about the sustainability of what the Fed is doing.
The British did it. The UK had a huge stock of foreign assets at the start of the 20th century. They had to be sold to pay for war, and that crushed the currency (they also had to do a huge amount of financial repression). The exchange rate in the mid-20s was $5, $2.50 after WW2, and is now closer to $1.
The Russians didn't have an Empire. The extent of their ambition was interfering repeatedly in the Balkans/Turkey for no reason, and (briefly) in Europe with the Prussian/Austrian war (and then having to dial back once Prussia gained in strength/Germany appeared/etc.)
The point about "debasing currency" is, however, nonsense and based on a misunderstanding of almost everything at play here. Perhaps most important: the US isn't an empire, having a large army doesn't mean you are an empire (if that were true, North Korea would be a world power), the role of the US is and has always been collaborative (this hasn't changed with Trump either, observing that Europe pays almost nothing into NATO seems quite fair).
Russia was the metropole of an empire not only under the czars but through the entire Soviet period.
> the US isn't an empire, having a large army doesn't mean you are an empire
The metropole dictating to peripheries does, whether the latter are formally independent or openly dependent territories does, and the US is a metropole which has many (and has had previously had more) of both kinds of peripheries.
An empire is a political unit that controls vast parts of the world and dictate their policies through military and economic means. This fits well on how the US operates. Unlike any other country, the US has military deployed practically in all continents and major oceans. The only difference between the US empire and the British empire is that the US likes to propagandize about the apparent freedom of their vassal states. In many part of the world, elections are only uphold if the elected support US policies (mainly through economic coercion), and when this doesn't happen the country is a target of coups, "regime change", or enters the "black list" of sanctions. For this reason, the US has several foreign spying and "regime changing" institutions, including the most famous CIA and NSA. All of this supported by mainstream US media, which has international reach and influence media in other countries. This is obvious with what happens at Venezuela, Iran, and Russia. More recently, China is entering the black list because it is increasingly seen as a threat to the US political hegemony.