Why is understanding precedent an important part of a judges role

The Importance of Precedent. In a common law system, judges are obliged to make their rulings as consistent as reasonably possible with previous judicial decisions on the same subject. ... Unless these laws are determined to be unconstitutional by the Supreme Court, they preempt the common law precedent cases.

Explanation:

the second significant cause of the great migration was the desire of black southerners to escape segregation, known euphemistically as jim crow. rural african american southerners believed that segregation - and racism and prejudice against blacks - was significantly less intense in the north.