At the start of world war ii, which country maintained an isolationist policy?

The United States was the major isolationist country.

Many other countries were already at war either because they declared war, or their colonizers declared war. Very few other countries remained as isolationist countries, as they saw benefit in joining either one side or the other.

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d. dr. francis collins

according to worldatlas.com, the u.s. has an 86% literacy rate.