Can a United States political party kick out a member? For example, could the Republican Party have kicked Roy Moore out? I am not talking about affecting the ballot, but removing his registration as a Republican so he can't vote in primaries, for example.
Party membership has a number of different meanings in different contexts. Let's start with the broadest definition and work our way in:
- The ability to vote in a party's primary is generally governed by state law. Some states (California, Louisiana) don't even have two separate primaries in the first place, while other states (New York) not only have separate primaries but make it unusually difficult to switch parties. There are occasionally issues of freedom of association, but for the most part, the parties have no control over any of these processes. They certainly cannot expel individual voters from their primary.
- The party's name appearing on the ballot in the general election is also governed by state law. In some states (California again) candidates may declare whatever "party affiliation" they see fit, while other states (New York) do involve the parties in the process (and New York again has complicated rules about withdrawing or modifying a party's nomination too close to the election).
- Officeholders "caucusing with" each other is not restricted by party at all. Bernie Sanders (I-VT) and Angus King (I-ME) both caucus with the Democratic Party in the Senate. If they began consistently voting against Democratic objectives, it is likely that the Democratic Party would ask them to leave the caucus. This is unlikely to actually happen given the current level of polarization in Washington. It is unclear to me whether a caucus could forcibly expel a member, but since they are private(ish) organizations, I think they most likely could find a way to do it if it became necessary.
- The ability of officeholders to vote for party leadership (i.e. the "majority/minority leader of the Senate/House" and similar positions such as the whips) is tied to caucus membership. If a party purported to expel a member for voting the "wrong" way in one of these elections, it would likely be a major scandal.
This is distinct from voting for the Speaker of the House or the President pro tempore of the Senate, which are both Constitutional roles voted on by the House or Senate at large (respectively). To become Speaker, the normal process is to win the party leadership vote first, then win the House-wide vote for Speaker. The President pro tempore is traditionally the most senior member of the majority party, although in theory the Senate could choose someone else by simple majority.
- The money provided to candidates running under a given party is determined by the national campaign committees for the Senate and House, for each party. As a data point, they did give money to Bernie Sanders in 2006 (and I imagine more recently), so independents are not categorically excluded. Independents can also help raise money for the national committees.
A party cannot expel a member of that party, because every citizen has the right to run for and be elected to public office (pursuant to whatever laws for qualification exist). All a political party can do with an unpopular candidate is withdraw their support and their nomination. That alone is sufficient to tank a person's candidacy, but it's not a legal matter, only a political one.
If such a candidate is actually elected despite their party's support, he/she can be ejected from the house to which he/she was elected, pursuant to whatever methods are available to unseat an elected representative.
So to use Roy Moore's U.S. Senate run as an example...
Let's say the Republican party withdraws support for him, but the people of Alabama elect him anyway. At that point, he is a sitting U.S. Senator regardless of Republican support. However, Article 1, Section 5, paragraph 2 of the U.S. Constitution states:
Each House may determine the Rules of its Proceedings, punish its Members for disorderly Behavior, and, with the Concurrence of two-thirds, expel a Member.
The Senate can, with a 66 vote majority, expel Roy Moore from their chamber, requiring Alabama to elect a different person, according to whatever laws they have for dealing with such a contingency. But at that point, Roy Moore is out.
They can probably prevent someone from participating in internal party-management types of activities, but, no, anyone who wants to declare that they belong to a particular party, as a citizen-voter, can't be stopped from doing that.
For many states, you don't ever have to declare a party to vote in primaries, but you can only vote in one primary or the other. For some of these states, voters are prevented from voting in one primary, and then voting in a different party's primary or run-off (sometimes there is a two-step primary where the top two party candidates advance to a run-off election to determine the ultimate party candidate for a seat), to prevent/reduce cross-over meddling from people not really interested in the good of the party.
(May 29, 2017) Alabama has a new law that prohibits voters from switching their political party allegiance between a primary and subsequent runoff.Alabama does not require primary voters to register with a political party.
The crossover voting ban is an attempt to prevent voters of one political party from trying to meddle in another party’s runoff – although there is a dispute about how much that actually happens.
“If you vote in one party’s primary, you can’t switch to the other’s runoff,” state Sen. Tom Whatley, the sponsor of the bill.