Question

The idea that an individual has a tendency to support the beliefs and practices of his own political party rather than those of the other party is called a multi party system. linkage. interest group. partisanship

Answer 1

I believe the answer is partisanship
partisanship makes a certain political party supporter blindly trust every action made by their political party despite the negative effect that it might cause.
People who engaged in partisanship tend to see the opposition of their party as the opposition of their personal value/principles.