Why do nations form alliances? give examples of different kinds of alliances and explain their purposes.

Nations form alliances in order to achieve goals that otherwise wouldn't be possible. For example, NATO, or the North Atlantic Treaty Organization, a coalition of countries in North America and Europe, agree to defend one another in case of attack from an outside party. This is clearly beneficial, because this intergovernmental support both makes an outside attack less probable, and if it occurs, easier to handle. Another example is NAFTA, or the North American Free Trade Agreement. Shared among Canada, the US, and Mexico, this alliance eradicated trade barriers within these countries. Another beneficial alliance, this agreement increases international trade due to lower costs and thus improves the international economy.
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