Is it safer for a country to have many different allies or to rely on one very powerful relationship?

„He who defends everything defends nothing.” - Frederick the Great

This is a good introduction, on my opinion to the topic on wheter a single powerful or multiple alliances are better.

A great example is how, if you had an alliance with a lot of countries like in Europe, where most countries are typically allied with each other, there isn’t a military deterence as big as the one that you'd have if you had a single alliance with the United States. Other advantages are that you would have a much easier time to allocate resources, intelligence (work) and work than you would have if you had multiple countries and each country would get a bigger share of raw resources. The last point is that there wouldn’t be any or at least almost no rivalry between the members, since they are only two and one is very powerful compared to the other one, therefore members could focus more on actually helping each other, rather than having a competion on who can build something better. A real world example of this is the Eurofighter Typhoon program, aswell as the FCAS program, where each time the French company „Dassault Systems“ couldn’t agree with the other companies on specifics, leading to them dropping out of the Programm.

However someone against a single alliance might argue, that if there is a disagreement big enough to get the countries to seperate or not trust each other as much. They could not help each other as much or even disband, leaving the other partner vulnerable. Similar to how US President Trump is actively worsening the relationships between it’s European/NATO allies and the USA. The Problem being that this is just worse if you had multiple alliances, due to the possibility of country A leaving your alliance, when have to act some way to maintain your alliance with country B, which displeases Country A leading to them either leaving or you significantly worsening relations.