In 2013, Jane Miller, a Republican in Brookfield, Connecticut, accepted a Democratic nomination for a special local election. She did not win. In April 2015, long after that election, the town Republican Party expelled her, under a little-used state law that lets parties expel members who are believed to be disloyal to the party.
Miller brought lawsuits in both state and federal court. Her state lawsuit alleged that the state law is unconstitutional, and her federal lawsuit charged that she had been denied equal protection because other Republicans who had also accepted the nomination of other parties had not been treated the same. On July 19, the town Republican Party reinstated her as a member, but both lawsuits continue, and the Republican Party still stands by its past action. Miller was not able to vote in the Connecticut April 2016 Republican presidential primary, so she does have a concrete injury. See this story.
The members of the Republican party who did this must have had a personal dislike for Miller. There have been several times in the not too distant past when the Republican candidate and the Democratic candidate were one and the same, with no repercussions from either party.
For example, in 2005 election for Mayor of Meriden, the choices presented to voters were:
Mark Benigni – Republican
Mark Benigni – Democrat
Arline Dunlop – Libertarian
I’ve seen that happen a few other times, too.