In hopes of denying Mayor Bill de Blasio a second term, some New York City Republican leaders intend to rally around a single candidate to avoid a contentious primary and present a stronger challenge in the general election. Starting this week, Republican Party leaders and members will begin the process of vetting candidates who have declared their intention to run for mayor or are exploring a mayoral bid. Party organizations will host public meetings where each candidate will have the opportunity to present their ideas to party voters and functionaries. When it fielded Joe Lhota in 2013 after a primary...