Is the United States on its way to losing its hegemonic status?

On the heels of President Trump pulling out of talks with North Korea over nuclear disarmament in the Korean peninsula, the United States' pending withdrawal from the Paris agreement (coming soon! ... the day after the next presidential election), and the United States' unilateral withdrawal from the Iran nuclear agreement, combined with ongoing Russian and Iranian leadership in resolving the Syrian civil war and Chinese leadership in talks with North Korea, we seem to be heading toward an ambiguous point in international geopolitics.

So this question is simple and nasty: Is the United States on its way to losing its status as the unquestioned dominant world power in the international order?

If it is on its way off the top of the food chain, who will challenge it? Are we returning to a cold war-style era or are the lines shifting and different? If the United States is not on its way to losing its dominant status, how might it maintain its footing in a world that seems increasingly disillusioned with it?