Complex sentence: During the campaign McCallister asked "Karen Carmichael" to be his running mate, but it was well known she had virtually no interest in the position of Vice President since the post had but vanished under the last two administrations.
Split into simpler sentences: During the campaign McCallister asked "Karen Carmichael" to be his running mate, but it was well known she had virtually no interest in the position of Vice President. The post had but vanished under the last two administrations.