The US has the world's most productive contiguous agricultural zone (the greater midwest) and that zone is overlayed by the world's largest contiguous navigable internal waterway system (the greater mississippi basin). On top of that you've got plenty of coal, oil, iron, etc and lots and lots and lots of very good ports.
And on top of THAT you have weak neighbors to the north and south and fish to the east and west.
It's tough to compare.
So to summarize, you need a power with reasonably secure borders, a unifying geography, resources, agricultural productivity, navigable waterways, and ports. Also, not too many powers who can rise up to challenge said power.
Since we're talking about the US, I'm going to limit my ideas to after US independence (1776?).
If Russia rolls all sixes, I guess it could work. But the issue with Russia is that the country is cold. Very very cold. So cold that they didn't finish building their first road across the country until the most recent decade (because concrete doesn't settle when it's that cold). The country's rivers flooding every spring doesn't help either. And you've got enemies in every direction, which limits capacity to be a truly global (as in take action anywhere you want) player.
The Rio de la Plata basin has the capacity to rival the US. Plenty of oil/gas, productive agricultural zone, navigable river, etc... but it's divided among 5 countries (Argentina, Bolivia, Brazil, Paraguay, and Uruguay). Had Argentina managed to keep Bolivia, Uruguay, and Paraguay as part of itself and expand at Brazil's expense, I think it could have been a pretty strong country.
Germany can be big and strong, but the country is very insecure. With threats in every direction, it is difficult to look beyond Europe. They did a good job OTL, but with France to the west, Italy to the south, the Scandinavians to the North, Russians to the east, British, etc... it's a tricky game to play.
If France gets its "Natural borders" and then some, you've got a pretty tough nut to crack. The Loire and Seine Rivers are very very agriculturally productive zones. The North European Plain is one of the few agricultural zones that can rival the greater mississippi, but it's been historically divided and the rivers alone the plain divide it further rather (allowing for various centers of power to emerge) rather than unite the place. France with it's natural borders has about 94 million people using 2019 population numbers. You've got a fairly secure boundary to the northeast via the Rhine, an ocean to the west, a maritime boundary to the north (although with a threat just across the pond...), mountains to the southwest and southeast, and a sea to play with (and potentially expand into) to the south. Meanwhile with the Atlantic to the west and mediterranean to the south, there's plenty of room for power projection. Just prevent a unified Germany from forming
or make sure it's a lesser Germany (something like the Confederation of the Rhine) that excludes Austria and Prussia and is tied to France.
- Algeria and Tunisia, on top of European France, gets you to 150 million.
- Ergo, reach the optimal boundaries and properly integrate and develop the areas within the boundaries and you could have a very powerful country.
- The Balearics, Sardinia, Sicily, Libya, etc. Call them cherries on top.
----------