It was just a matter of time before Lousiana Rep. Anh “Joseph” Cao, the country’s most vulnerable Republican, had an official Democratic challenge. It came Tuesday in the form of state Rep. Cedric Richmond, who formally launched his campaign in New Orleans, promising to “reject partisanship, corruption and ineffectiveness.”

Richmond has long been expected to join the race. He ran and lost in the crowded 2008 Democratic primary to corruption-tarred nine-term Rep. William Jefferson, but did earn the endorsement of one the district’s major papers, the New Orleans Times-Picayune. And he will be a favorite to win the the black-majority 2nd District, which gave three-fourths of its votes to Democrat Barack Obama in the 2008 presidential election.

In the last election cycle, Cao benefited not only from the scandal surrounding Jefferson, who was convicted of federal corruption charges Aug. 5, but also the fact that a hurricane in early September delayed both the primary and general election by a month.

Democrats are now gunning to retake the seat, but could first have to get through a crowded primary. Another Democrat interested in the seat is State Rep. Juan Lafonta.

CQ Politics rates the race Democratic Favored.