A House primary in Detroit pitting two Democratic incumbents against each other has taken on heavy racial overtones — with many in the African-American Democratic establishment backing the white candidate, Rep. Gary Peters over Rep. Hansen Clarke, who is African-American and south Asian.

The Wayne County Democratic Black Caucus endorsed Peters on Thursday, making it the latest group to throw its support to the congressman.

Peters also has the backing of the American Federation of State, County and Municipal Employees (AFSCME) and many local unions, a powerful bloc in the labor-heavy district. Clarke has yet to secure many high-profile endorsements, and according to a few local sources has not been pushing hard to do so.

Part of Clarke's problem might stem from his winning primary run against former Rep. Carolyn Kilpatrick (D-Mich.), which infuriated many African-American power-brokers in the Detroit Democratic establishment. But some of the opposition might also come from his biracial background — his father was a Bengali immigrant from India.

"Many people don't feel that Hansen is necessarily black, to be quite blunt, especially since he's been on TV saying he’s the first Bengali congressman," said Michigan state Rep. Lamar Lemmons (D). "Some people feel like he's abandoned us."

When The Hill reached out to his campaign for comment, Clarke immediately called back.

“Mr. Lemmons is bitter — he’s always had an issue that I’m biracial,” he said with an edge to his voice when asked about the comment. “It’s a shame that people want to use someone’s racial background in this way. It’s really my strength — being south Asian and African-American, growing up in the inner city on my own without parents since I was 19 — we need someone who was born and raised and never left the city; I know what people go through.”

Clarke beat Lemmons in a 2006 state Senate race despite Lemmons having the support of most of the Detroit Democratic machine, including then-Mayor Kwame Kilpatrick (D), Rep. Kilpatrick’s son, who later served jail time after a scandal. 

Peters has a more centrist voting record, although both have sought the "progressive" mantle in the race, and represents a suburban Detroit swing district that was dismantled by Republicans in redistricting. Clarke needs to do well in the Detroit portion of the district in order to win.

Organized labor could be a major stumbling block for Clarke; unions are a powerful force in Democratic primaries, especially in Detroit. But while he admitted he’d sought their support, he said he wasn’t worried about their backing Peters.

“Most of those [union endorsements] were already predetermined; the majority of those held no interviews, they were decisions that were made by certain people,” Clarke told The Hill. “The official endorsements aren’t going to matter in this kind of race; it’s about mobilizing the people.”

He pointed out that he’d taken on the establishment Democrats and won four times and taken the last three races — he beat an incumbent state senator in 2002 as well. With each run he increased anger from the party.

But this time, the calculus is different: The new congressional district stretches far out into the Detroit suburbs in Oakland County, Peters’s power base as well as Clarke’s, making his ability to win votes in the city even more crucial — and the unions’ and local party’s get-out-the-vote efforts in what will be a low-turnout August primary even more important.

Clarke has made his political career out of angering the predominantly black Detroit Democratic machine. Now it might have an opportunity to get even.