Many americans resent it and discriminated against the new immigrants to the u. s. what was this anti-foreign attitude called

Nativism

Explanation:

The Nativism was a policy that was implemented by the US to protect the interests of the native-born or established inhabitants of the country against those of the immigrants. In other words, the policy was  a semi-discriminatory policy. The policy became a general ground for the opposition to immigration based on the unfounded fear that immigrants would spoil the pure American culture. Nativism was about preserving cultural change.

the speech convinced americans that the ussr was an enemy, rather than an ally, which led to the creation of the truman doctrine.