Is it possible for a country to be a world hegemon without the use of military force?

The concept of hegemonic power has always been made up by two side of the same coin: the hegemon should be by far the most powerful international actor in the international scene from a mere military point of view, helped in this goal by the most prosperous economic system in comparison with the other ones. This dichotomy has hardly ever been broken in single pieces, but the current international situation may suggest that this trend is on the verge of an evolution. Is it really so?

According to the main theoretic background on the subject, in order for a nation state to rise to the level of hegemon, there are some attribute it must have. Namely, political strength, military force and superior national power are the necessary elements for a power to strive to become hegemon. The hegemon must also have a large and growing economic, beside having the will to lead the international order and commit to the system.
According to Thomas J. McCormick, the hegemon is “a single power’s possession of ‘simultaneous superior economic efficiency in production, trade and finance’”. John J. Mearsheimer, the main representative of the so-called offensive-realism, states instead that the system is mantained and shaped by a hegemon through coercion, and military power is a widely used mean to express national interests in case those are threatened. 

Would it be possible for a state to impose itself as a hegemon without the use of force?

The main point in this overall discussion is not only about whether it is possible or not to become hegemon without the use of force. Rather, it is important to analyze the process of succession from an hegemon to another without military conflict. 
According to the realist theory, every major power feeling endangered in its national interest would at last decide to use the military might to impose its will. Therefore, according to this theory, it seems like the succession cannot take place without a military confrontation. 

Gilpin's argument contends that the system naturally goes toward equilibrium. To acquire a new system, global war or "hegemonic war", definitionally creates a new hegemon. This new hegemon will create the new system of the world with their own set of preferences. Gilpin argues further that by the global system, the more decisive a victory is after the "hegemonic war", the more stable the new system will be.
Nevertheless, it is needless to say that in the current system the best way to impose a state superiority is through economics ties. The hegemon seen as benign and ensuring economic growth for all of the countries revolving around it has a competitive advantage over a hegemon which imposes itself through coercion, therefore paving the way for a possible succession.
This become inevitable especially in the case in which the former hegemon has already turned “predator”, ruining the relations with the countries laying in its sphere of influence. If the new hegemon manages to slip into the economic fabric of those countries, showing the benefits for a closer collaboration with it, there would be in principle no need for massive military intervention, for the fait accompli would put the former ruler outside of the game.
The discourse about hegemony has come back to the interest of scholars especially in the last years, with an international situation in everlasting evolution and with new dynamic players on the international scenario. First of all, China is lately subject of great academic interest according to the economic boom it has witnessed in the last decades. Many scholars claim that the XXI century will be the Chinese one, with China destined to surpass U.S. GDP by 2050 or even before, and with the U.S. steadily loosing its grip on the international system.
In this discussion it is important to analyze the events which troubled international relations approximately in the last two years. China has promoted a major infrastructural project, the One Belt One Road initiative, which is supposed to link Asia, Europe and Africa with new commercial routes and new massive flows of investment in infrastructural project in every country which may be interested in participating in the initiative. China, paradoxically, became the main flag of international economic liberalism, taking advantage from the election of Donald Trump as president of the United States.
Donald Trump, in fact, has gone against those structures which were supposed to project multilateralism in an institutional framework, such as the Trans-Pacific Partnership and the Transatlantic Trade and Investment Partnership, paving the way for new actors to strive for imposing economic hegemonity in the international sphere. Furthermore, the exploration of the Arctic area by Russia and the will to use the Arctic routes for Chinese trade has incremented the perception of a loss of authority by the U.S., which lag behind the other powers in the race toward this new territories.
China is massively investing especially in Europe and Africa, so to ensure the realization of its colossal project. Despite suspicious, even European states are openly welcoming Chinese presence in their territories, and the Chinese position in Africa is long consolidated, especially after the opening of the first Chinese military base abroad, in Gibuti, the last year.
Nevertheless, it would be overrated to think that China will soon overcome U.S. in the role of global hegemon. U.S. has the biggest army in the world and invest significantly more than any other country in the defence sector, which ensures it a superior military position. It is true nevertheless that the U.S. are currently suffering from imperial overstretch, with troops operating in about fifty-five countries which could definitely harm in the long period the capacity to hold this hegemonic position in the long term. With the second highest gross domestic product at purchasing power parity, China poses a significant challenge to U.S. economic primacy especially with the expectation that U.S. national debt could explode to 717% of GDP by 2080 according to Congressional Budget office. Moreover, this debt is financed largely by China through the purchase of U.S. Treasury bonds. As Global Trends 2025 points out, the rise of China and India to great power status will restore each to the positions they held two centuries ago, when China produced approximately 30 percent and India 15 percent of the world's wealth.
In this case scenario, according to realist theory, a conflict among these powers would turn out to be inevitable. It is now impossible to forecast any realiable scenario, but at the same time, for how extreme it may sound, the military one is an option not to exclude a priori.
This example just analyzed underlines the importance of the military factor in the establishment of an hegemon in the international system. Nevertheless, I think China is, until today, a good example of a power trying to impose itself merely through the economic factor. Therefore, is it possible for a hegemon to refuse to adopt hard power as a mean to establish itself as a power?
According to the literature existing and to the examples we have in our world today, it would be not possible. I would partly agree with this theory: in fact, a hegemon cannot avoid having an extremely powerful and effective army, but this does not mean that it should be employed actively. In fact, the deterrence of a mighty army would most of time be enough to dissuade possible rivals to attack the hegemon, for the outcome of a possible conflict would be evident.
Effective diplomacy, mutually beneficially economic development and a great power of deterrence are the element which are needed nowadays for a country to impose itself on the international scenario. We can therefore say that the use of military power may, according to certain specific circumstances, be avoided.
An effective economic cooperation, with a network format rather than a hierarchic structure would ensure a more reliable fidelization of the countries involved in the sphere of influence of the hegemon. The other states must realize the actual benefits of the participation in the economic network of the hegemon, a network in which everybody would develop its own competitive advantage, with the possibility to create a system in which no one would put into question the role of the hegemon itself but every part of the organism would result essential for the overall functioning of the system.
The role of the hegemon would not be put into question merely because of its overwhelming military superiority. This would not just include a substantial nuclear arsenal, powerful navy and air forces, but also an advanced and effective system of intelligence and cyber-security. To create a security structure involving as much actors as possible would be a further insurance for the maintenance of the overall system, pushing aside the risk of conflict and deterring those outside actors, which could try to challenge the system itself.