Maintaining international stability while reducing US military influence

Question

The US military is currently maintaining a status quo around the world, including preventing military aggression against smaller democratic nations and keeping shipping and international trade open and equal for the participation of more nations. Conversely, the US military is very expensive for American citizens to maintain and is a great source of anti-American sentiment, as the US is meddling in all nations' international and often internal affairs.

Libertarians propose that a good solution to reduce the nations debt and end the US's unending series of wars is to reduce the US's military influence globally by reducing the number of bases in foreign countries and withdrawing from traditional areas of hegemonic influence, such as in South Korea.

When I ask libertarians what will happen to countries dependent on the US military, mostly I get response of: it's not a concern or its not the US's business anyway. But have there been solutions proposed for how American allies greatly dependent on US military influence will pivot diplomatically and militarily to evolve to these changing circumstances? Perhaps an academic has attempted to answer this question specifically, but if not:

Edit: Nations I am seeking information on. I do not expect answers to include all requested information: Germany, France, South Korea, or Japan

Politically, how would Japan and/or Germany transition to normalizing use of military forces as they currently are using "defense forces."

How much would defense budgets need to be increased to make up for complete withdrawal of American military involvement in these regions?

Are current military/diplomatic alliances in these regions adequate to countering potential aggression, especially considering that aggression and disputes over borders, shipping lanes and natural resources may increase with the withdrawal of the US?

Answer 1

The US military is currently maintaining a status quo around the world, including preventing military aggression against smaller democratic nations

Debatable. Some people hold the US responsible for making al-Qaeda the powerful organisation it is now, for massacres in South America, etc.

and keeping shipping and international trade open and equal for the participation of more nations.

I doubt it. Some countries were essentially strong-armed into agreeing to bizarre American IP laws (more on Wikipedia).

Libertarians propose that a good solution to reduce the nations debt and end the US's unending series of wars is to reduce the US's military influence globally by reducing the number of bases in foreign countries and withdrawing from traditional areas of hegemonic influence

Yes, but that's a roundabout way of looking at it. The non-aggression principle is central to many libertarian ideologies. I'll leave aside anarchist libertarians for the time being, as they consider all taxation as theft, and don't believe in nation-states. Since your question seems to be accept the nation-state as a given, I'll consider only the minarchist approach to an answer. Minarchists tend to consider the government as a necessary evil, and therefore prefer to limit its power to only act where it is absolutely necessary: internal and external security, and the judiciary. These principles cannot justify the situation where the US becomes the de facto policeman of the world. And it has the incidental benefit of not wasting taxpayers' money.

what will happen to countries dependent on the US military

The EU shows how countries can work together for mutual protection.

Nations I am seeking information on. I do not expect answers to include all requested information: Germany, France, South Korea, or Japan

Germany and France are not dependent on the US in any way. This may have been true, to some extent, during the cold-war era, but that's not the case now. South Korea and Japan would have to ramp up their forces, create new alliances with other countries, etc.

Politically, how would Japan and/or Germany transition to normalizing use of military forces as they currently are using "defense forces."

Germany is doing fine by itself. As for Japan, I can't answer the "how" except by pointing to all the other countries that have adequate defense programs.

How much would defense budgets need to be increased to make up for complete withdrawal of American military involvement in these regions?

Depends largely on what kind of countries they form alliances with, and what kinds of aggressors they have to fear.

Are current military/diplomatic alliances in these regions adequate to countering potential aggression, especially considering that aggression and disputes over borders, shipping lanes and natural resources may increase with the withdrawal of the US?

I don't know the details, but it sounds unlikely that Japan and South Korea have adequate defense programs already... but that's because they have defense agreements with the US. If these agreements are dissolved, they'll have to seek other partners. But if South Korea, Japan, and the US can best serve their citizens with this alliance, there is little reason to dissolve it.