Usually countries have to decide between butter and guns (eco 101). Well, such “largest militaries on Earth” had it both! Like Switzerland, you do have to keep a strong military to dissuade, but aligning to a alliance when you are the spearhead is bad. Switzerland had made an alliance with France or Germany a century ago, would not have ended non invaded, 100% guaranteed.
Usually countries have to decide between butter and guns (eco 101). Well, such “largest militaries on Earth” had it both! Like Switzerland, you do have to keep a strong military to dissuade, but aligning to a alliance when you are the spearhead is bad. Switzerland had made an alliance with France or Germany a century ago, would not have ended non invaded, 100% guaranteed.