EDMONTON—The two parties vying to form the next Alberta government are offering voters a stark choice, but it’s as much a battle of personas as it is politics. As former Progressive Conservative premier Alison Redford said this month, “It’s not as easy to distinguish what is an NDP idea from a conservative idea anymore.” This election, which concludes as voters head to the polls Monday, has seen the United Conservative Party appealing to nurses, child-care workers and skilled tradespeople, while the NDP has offered tax incentives to certain businesses for low-emissions projects. Both parties sell themselves as strong supporters of...