Power and influence are relative conditions, not absolute. Other nations are much weaker. Accordingly, in the real world we are relatively stronger than before. Now, unlike power, economics is not generally a zero-sum game. America is better off economically when other nations also do well.
Wealth spreads, and increased global trade has been salutary.
Our own market comprises nearly 300 million people, with the highest per capita income. We have a full complement of necessary natural resources. The proportion of the American economy in international trade has grown in recent decades. Imports and exports made up 10 percent of the economy in 1954. By 1994 that proportion had climbed to 28 percent, of which about 12 percent is in exports, the potentially vulnerable area.