Bill Casey

William David "Bill" Casey, the Conservative MP for Cumberland—Colchester—Musquodoboit Valley in Nova Scotia, was expelled from the Conservative caucus on June 6, 2007, after voting against the Harper government's budget. Casey's objection was specific and principled: he believed the budget violated the 2005 Atlantic Accord, which had promised Nova Scotia and Newfoundland the full benefit of their offshore oil and gas revenues. Casey argued the budget's equalization formula clawed back these revenues, breaking a solemn commitment to Atlantic Canada. Stephen Harper's office immediately expelled him from caucus.

Casey ran as an Independent in 2008 and won re-election handily, demonstrating — like Nunziata before him — that personal integrity can trump party loyalty with voters. He retired in 2011 but returned to politics as a Liberal candidate in 2015, winning comfortably. He retired again in 2019. Casey's case became a leading argument for those who believe MPs should represent their constituents first and their party second.