It looks like Pressler formerly left the GOP in 2013 and hasn't ever returned to the fold, Arne Carson was officially BANNED from Minnesota GOP events by the state Republican central committee after he continually endorsed RAT initiatives like Walter Mondale's campaign against voter ID laws, and the only time William Milliken endorsed a Republican after leaving office was briefly supporting McCain for President, an endorsement he later rescinded.
I'm reminded about how the media continually refers to Lisa Murkowski as a "Republican" when she lost the GOP nomination and then launched a campaign to defeat the Republican nominee. Perhaps the most vile example is Colin Powell. He and the media continually refer to him as a "Republican", but aside from serving under Republican Presidents, has this guy EVER endorsed a Republican Party initiative? Has has even endorsed or campaigned for a fellow "Republican"?
Powell backed GW Bush in 2000, I recall ending a rally and he was present and he spoke at the convo.
I also found reference to him endorsing RINO Senator Jim Warner in his 1996 primary against a conservative.
Wikipedia says he began endorsing GOP candidates in 1995 when he was exploring a run for President, but it doesn’t name them.