In the course of a Matthew Yglesias off of a David Leonhardt column, it would appear that American economic growth overtook the great Western European powers during the 1870s. This is great and salient news for the American Way.
Why? Because the maturation of American hegemony came nearly 75 years later. You could date the dawn of America as a global great power to the voyage of the Great White Fleet during the Teddy Roosevelt administration. That's pretty much 30 years of lag time between economic supremacy and commensurate geopolitical heft. From there, it would be another 30-ish years before we ended up one of the two last superpowers standing, with an outsized military presence on the planet and the ability to shape global events (along with those other guys).
So cheer up, fellas! If the Chinese follow in our footsteps, they're not due to overtake us militarily for decades yet.
Obviously that's flip and superficial, and there's more difference than similarity in the rise of China and the rise of the United States. (We were an hegemonic power in our own hemisphere since the early 19th Century; China started flirting in earnest with regional hegemony in late 2009 and it ended up pushing regional players into the U.S. orbit.) But the point is that even if we assume the absolute worst about Chinese geopolitical intentions and the absolute most about Chinese geopolitical ambitions, it's going to be decades before they reach our weight class. And so much of geopolitics is about getting the other powers to bandwagon with you. No one will be looking to China -- a nation touting a refurbished, ancient aircraft carrier as its (for now) prized naval platform -- for security guarantees for a very long time. And even when China is a viable alternative competitor, nations are going to think long and hard about risking their relations with the United States. Even if China is the mightiest economic power around.
Of course, if we go into total insolvency, then that's, like, a wild card.