Rep. Jesse Jackson Jr. Resigs from Congress

Representative Jesse L. Jackson Jr., who has received a diagnosis of bipolar disorder and has been under federal investigation, will resign from Congress on Wednesday.

Aides to House Speaker John A. Boehner said Mr. Jackson sent his office a letter with his intent to resign.

“For seventeen years I have given 100 percent of my time, energy and life to public service,” Mr. Jackson wrote in his letter to Mr. Boehner. “However, over the past several months, as my health has deteriorated, my ability to serve the constituents of my district has continued to diminish. Against the recommendations of my doctors, I had hoped and tried to return to Washington and continue working on the issues that matter most to the people of the Second District. I know now that will not be possible.”

In his hometown, Chicago, and in Washington, the decision puts an end to five months of speculation about the political future of Mr. Jackson, a Democrat and the son of the civil rights leader bearing the same name, who had vanished from Congress and public view since June.

Still uncertain for Mr. Jackson is how a criminal investigation into his possible use of campaign funds on purchases for his home may turn out.