To preserve peace, President Eisenhower deterred the enemy by threatening to use nuclear weapons, a policy known as

Nuclear blackmail

Explanation:

To preserve peace, President Eisenhower deterred the enemy by threatening to use nuclear weapons, a policy known as "NUCLEAR BLACKMAIL"

Well, Nuclear Blackmail is a term, technique, or policy whereby the aggressor in a dispute uses the threats of nuclear weapons to fight or destroy his opposing side, just to do his bidding. The threats of nuclear blackmail are sometimes related to brinkmanship.

Hence, in this case, the correct answer is NUCLEAR BLACKMAIL

- encouraging nationalism

- returning to conservative political policies