The term was taken from Senator Joseph Mccarthy. During the Second red scare in the 1940s and 1950s, there was a fear in America that the soviet union somehow managed to expand their influence within United States and took control of the united states government.
Senator Joseph Mccarthy use this fear to make several accusation toward his political rivals. He accused that these rivals somehow the supporter of Communism even without having any solid proof. It's a fear mongering tactic that he used to obtain support from the people to strengthen his position within the government.
Germany promised Mexico all the land that they lost in the Mexican- American War. Mexico did not agree with the fact that they had a lot of political problems and were in no shape to fight the United States.
