Some writers implied that there is a moral imperative for Christians to form a separate political party, as if membership in a non-Christian party is an unequal yoking with unbelievers. The rule also applies in church matters where the same apostle tells us not even to associate with apostates. But he makes great pains to specify that he is talking about the Church. Relationships such as employment contracts are permitted. A relationship such as membership in a political party does not require life-long commitment, but Christian baptism or Christian marriage do.
Baptism is forever.
Party membership is until you resign or miss two consecutive elections. If advocates of this view really want to be consistent, they should consider revoking their U.S. citizenships. That having been said, there are some who imply something like an ethical obligation to stay in the two- party system. There are hints that it would be a violation of Christian charity, and insensitive to form our own party. I cannot agree with this.