The top election official in Arizona’s most populous county will get more authority in running elections after a judge sided with his office in a prolonged legal fight with the county board that shares responsibility for overseeing voting. Justin Heap, the Republican recorder in Maricopa County, sued the predominantly Republican county board of supervisors last summer, alleging it had illegally taken control of certain aspects of election administration. Superior Court Judge Scott Blaney largely sided with Heap’s office in his ruling, which was filed Thursday but appeared on the public docket Friday. The decision could have broad implications in one of the nation’s biggest battleground states, which will have several high-profile races this fall.