Final answer:
The factor that benefited the Republican Party in the 1970s was the political shift and realignment happening in the United States at that time.
Step-by-step explanation:
The factor that benefited the Republican Party in the 1970s was the political shift and realignment happening in the United States at that time.
The Democratic Party, which had traditionally held control, faced challenges due to internal divisions and changing social issues.
This provided an opportunity for the Republican Party to attract different groups of voters such as Southern Democrats and conservative Christians who were looking for smaller national government, greater states' rights, and traditional family values.