Some old timey RINOS got ACU scores approaching zero. The likes of Jacob Javitz and Chuck Mathias, a near party switcher. Generally nobody that liberal is a Republican anymore, even in NY (other than Bloomberg’s fake Republican sojourn), State Senator Roy Goodman of the Upper East Side of Manhatten may have been the last one close to that ilk in significant office, worse than Dede Scuzzobama.
The most liberal Republican in Congress in recent memory was Connie Morella, easily worse than any serving today, I would say. From her district, anything better than 100% moonbat dem was good. Jim Jeffords didn’t go full moonbat till he switched.
Roy Goodman passed away not long ago. He was a lefty, but well liked personally, even by the most conservative Republicans who served with him. Connie Morella was also well liked personally by her caucus in spite of her voting record.
Here is his obituary: