Can American political parties expel members?

In the United States, political parties like the Democrats and Republicans do not have a formal mechanism to expel members. Unlike some other countries where parties can formally expel members for various reasons, such as damage control, prevention, or deterrence, American parties generally do not have this capability2.

However, parties can influence their members through various means, such as not supporting them in elections or applying internal party rules. For instance, parties might not endorse or fund candidates who do not align with party values or who have caused embarrassment. This is more about political pressure and less about formal expulsion2.

In contrast, the U.S. Congress has the constitutional authority to expel its members. Article I, Section 5 of the Constitution grants each house of Congress the power to expel a member with a two-thirds majority vote, typically for disorderly behavior134. This power is distinct from exclusion, which involves refusing to seat a member-elect1.

Thus, while American political parties cannot formally expel members, Congress has the authority to expel its members under specific conditions.