She didn’t become a Republican as far as I know. Which means she is now an independent swing voter. That’s not unusual. The Democratic party affiliation averaged 45% of the electorate from FDR until Reagan. Those who identify as Democrats are now down to 29%. The Republicans have been stuck at 26-28% on average ever since IKE left office. It’s independents that has grown from 20% during Eisenhower up to 43% today.

https://www.pewresearch.org/politics/interactives/party-id-trend/

Independents, swing voters continue to rise as more and more people are coming to the conclusion that neither party represents them. I wouldn’t be surprise if independents, swing voters pass the 50% mark in 10-20 years.

It's high past time that we start electing Americans to congress and the presidency who put America first instead of their political party. For way too long we have been electing Republicans and Democrats who happen to be Americans instead of Americans who happen to be Republicans and Democrats.