Question

why was nato formed

Answer 1

It was a response to the threat the Western allies[Great Britain,France, USA,etc] thought that the USSR posed.

Answer 2

In Post WW2 Europe, the USSR had gained control of most of Eastern Europe as a result of driving the Germans out. Stalin promised free and fair elections, but turned that promise into a farce. The USSR had military forces estimated at 3 times the size of the combined allied forces, and an airforce that dwarfed the rest of the allies. In response to this the USA countered with the Marshal Plan ( to rebuild the shattered Western European economies), NATO to protect Western Europe. The USA also utterly backstabbed Britain over it's war debt, leading to a generation of comparative stagnation and the collapse of it's empire, while former Axis countries rebuilt far faster.

Answer 3

ussr break down