Complex sentence: Some members of the Waffle remained New Democrats but Laxer, Watkins accepted Lewis' ultimatum and quit the NDP in 1972 and continued the Waffle under the official name, the Movement for an Independent Socialist Canada, but still commonly referred to as the Waffle.
Split into simpler sentences: Some members of the Waffle remained New Democrats, but Laxer and Watkins accepted Lewis's ultimatum and quit the NDP in 1972. They continued the Waffle under the official name the Movement for an Independent Socialist Canada, but it was still commonly referred to as the Waffle.