Debatably the US is a merged country (originally a confederacy of independent states, decided to bind themselves together). Similarly, you could say that the EU is. The USSR’s control over a number of smaller states (eg. Poland, East Germany) could count as well.
Generally though, I’d say that the incentives are against it on multiple levels. The politicians are against it because they’d lose some level of power, unless it’s a complete takeover, in which case the other side is losing significant power. The bureaucrats are against it because combining country-wide systems would be very difficult. And the people are against it because of nationalism and the intersection of nationalism and ethnic groups. Many Americans wouldn’t want to merge with Mexico because they want to be separate from the Mexicans. Most Serbians want to have their own country separate from the Croatians’ country. People like self-determination.
USSR itself formed by the merger of the Ukrainian Soviet Socialist Republic, Transcaucasian Soviet Socialist Republic, Beylorussian Soviet Socialist Republic and Russian Soviet Socialist Republic in December 1922. It is believed that Joseph Stalin preferred the other states to be annexed into Russia, while Lenin, the then Prime Minister of Russian Soviet Republic, favored a federation.
Debatably the US is a merged country (originally a confederacy of independent states, decided to bind themselves together). Similarly, you could say that the EU is. The USSR’s control over a number of smaller states (eg. Poland, East Germany) could count as well.
Generally though, I’d say that the incentives are against it on multiple levels. The politicians are against it because they’d lose some level of power, unless it’s a complete takeover, in which case the other side is losing significant power. The bureaucrats are against it because combining country-wide systems would be very difficult. And the people are against it because of nationalism and the intersection of nationalism and ethnic groups. Many Americans wouldn’t want to merge with Mexico because they want to be separate from the Mexicans. Most Serbians want to have their own country separate from the Croatians’ country. People like self-determination.
USSR itself formed by the merger of the Ukrainian Soviet Socialist Republic, Transcaucasian Soviet Socialist Republic, Beylorussian Soviet Socialist Republic and Russian Soviet Socialist Republic in December 1922. It is believed that Joseph Stalin preferred the other states to be annexed into Russia, while Lenin, the then Prime Minister of Russian Soviet Republic, favored a federation.