When was it the rats first won the legislature? As far as I can surmise it was 1986.
Weird stuff it Vermont with the supposed strict ladder of succession to office working your way up to US Senator.
I talked online to this guy allegedly the scion of rich Vermont family, he said his family knew Jeffwhores. He was thrilled with party switch.
Going by the elected leadership (Speaker in the House, President Pro Tempore in the Senate), the Democrats first won the VT House in the modern era in 1974. The GOP took it back in 1980, but ironically lost it in 1984. They didn’t get it back until 2000 (due to the unpopularity of Dean) and lost control in 2004.
In the Senate, they got control in 1984 for the first time in the modern era, lost it in 1992 (go figure), reclaimed it in 1996, and have never lost it since. The first Dem President Pro Tempore in the modern era was Peter Welch, now the Congressman.