PHOENIX — For six years, the self-proclaimed toughest sheriff in America has vehemently denied allegations that his deputies racially profile Latinos in his trademark immigration patrols.

Joe Arpaio would dismiss his critics in his signature brash style at countless news conferences and in numerous appearances on television.

Now, the sheriff in Arizona's most populous county will have to convince a federal judge who is presiding over a lawsuit that heads to trial on Thursday and is expected to last until early August.