State Sen. Bert Johnson (D-Mich.) announced last week that he’ll challenge Rep. John Conyers (D) in 2012.

Johnson told Roll Call on Monday that he decided to challenge Conyers because “I am the 21st-century version of what a Congressman needs to be for his district.”

Conyers has won re-election easily throughout most of his career in his Detroit-based district. But Michigan Republicans recently passed a new House map that moves Conyers into a district with mostly new territory, potentially endangering the 24-term Democrat. Johnson does not live in the newly redrawn district, but he says much of his current legislative district is in it.

“I’m absolutely a strong candidate because the remainder of my Senate seat is within that district,” he said. “But more importantly, these are people I’ve interfaced with in the last 10 years.”

Conyers, the House Judiciary ranking member, could be vulnerable for another reason. His wife was sent to prison for bribery earlier this year.