Which best describes a main reason many western european nations joined nato in 1949?

To defend each other against attacks by responding with force.

Explanation:

The main reason many western european nations joined nato in 1949 is To defend each other against attacks by responding with force and it states that a military attack to any of its members is an attack to all members.

The conversation between Western nations arrived at a conclusion on April 4, 1949. This involves the foreign minister of 12 countries in North America and Western Europe coming together in Washington DC to sign and endorsed the North Atlantic Treaty.

Nato (North Atlantic Treaty Organization) original members includes France, Belgium, Britain, Canada, Denmark, Iceland, Luxembourg, the Netherlands, Norway, Portugal, Italy and the United States.