Complex sentence: Jackson's one-on-one campaigning skills, which were so successful in Washington state, did not translate as well on the national stage, and even his supporters admitted he suffered from a certain lack of charisma.
Split into simpler sentences: Jackson's one-on-one campaigning skills, which were so successful in Washington State, did not translate as well on the national stage. Even his supporters admitted that he suffered from a certain lack of charisma.