(Reuters) - Longtime Detroit-area Democratic congressman John Conyers' bid for reelection suffered a blow on Friday when state officials said errors in his nominating petitions left him without enough valid signatures to appear on the primary ballot.
The Michigan Secretary of State's ruling came after local elections officials earlier this month tossed out hundreds of signatures collected by campaign workers for Conyers, 85, who was first elected to Congress in 1964 and is second in seniority in the body.
Both state and local election officials said the signatures had errors and were gathered by people who were not registered voters in Michigan.
Conyers was required to submit at least 1,000 valid signatures to appear on the August primary ballot. The Michigan Secretary of State's office found that Conyers had just 455 valid signatures.
Conyers is challenging in federal court the Michigan law requiring the circulators to be registered voters in the state. A judge in Detroit is expected to rule as soon as Friday.
If his appeals fail, Conyers could attempt to run as a write-in candidate.
The liberal Conyers is one of America's most prominent black politicians and is a former chairman of the U.S. House of Representatives' Judiciary Committee.
Conyers' district is solidly Democratic. President Barack Obama won 85 percent of the vote in the district in his 2012 re-election, according to Democratic Party records.
Conyers ranks second in seniority behind fellow Michigan Representative John Dingell. Dingell, who is retiring this year, is the "dean" of the House, having arrived in 1955.
(Reporting by David Bailey in Minneapolis; Editing by Grant McCool)