First, there are reports of new evidence linking him to a plan to purchase the U.S. Senate seat vacated by President Obama.
Jackson, Jr. also says he's sorry for disappointing people by having a relationship with a female acquaintance named Giovana Huidobro.
In a statement, the congressman says he did nothing legally wrong and he vows to remain in office.
It does not get much worse than this for a U.S. congressman on the ballot for re-election six weeks from Tuesday who also might want to run for mayor of Chicago five months from now.
He still has not been charged with any criminal offense, but politically, Jesse Jackson, Jr. is in a world of trouble.
Tuesday morning's Chicago Sun-Times reported the new allegation that Congressman Jackson, Jr. on October 8th, 2008 directed political fundraiser Raghujiveer Nayak to raise campaign cash for former Governor Rod Blagojevich in return for an appointment to the U.S. Senate.
A grainy photograph taken outside the White House puts Jackson, Jr. and Nayak together that day.
Jackson, Jr. has repeatedly denied he was aware of any transaction.
The newspaper also reported that Giovana Huidobro, a "social acquaintance" of Jackson, Jr. also attended the meeting, and that Nayak told the FBI that on two occasions he bought roundtrip airline tickets for Huidobro to fly from Washington to Chicago.
"I don't think he could possibly run for mayor at this point," said political consultant Delmarie Cobb, who helped Jackson during his first run for congress.
She bristled last week when the congressman told a radio program the feds should "bring it on" if they had any evidence to link him to an attempt to buy a senate seat.
"The last thing you want to do is to say 'bring it on,' because you have no idea what they have on you," said Cobb.
According to the Sun-Times, Huidobro is a hostess at a Washington, D.C. nightclub where Congressman Jackson, Jr. reportedly has held fundraisers. Jackson, Jr.'s mistress was revealed on the front page of the daily newspaper hours before his politician wife's birthday party.
He issued a statement this afternoon saying: "The reference to a social acquaintance is a private and personal matter between me and my wife that was handled some time ago. I know I have disappointed some supporters and for that I am deeply sorry."
The congressman's Republican opponent in November, Isaac Hayes, said he was not surprised by the widening scandal surrounding the incumbent.
"I was not surprised but I was certainly disappointed that we learned there's a greater involvement by the congressman in the Rod Blagojevich Senate seat scandal," said Hayes. "I think the voters have had enough with our current representative with just his entanglement with Rod Blagojevich."
Hayes declined to get involved in discussing Jackson, Jr.'s alleged personal issues.
"Any issues of illicit affairs is something I don't want to address," said Hayes. He did suggest that Jackson, Jr. should "resign and focus on his family, focus on the legal issues he has before him."
Cobb said she wonders why the Republican Party is not giving Hayes more financial support.
"There's something wrong with the Republican Party both locally and nationally if they don't jump into this race," said Cobb.
So far the Democrats have considered Jackson's to be a "safe seat".
Illinois Republican Party Chairman Pat Brady says he has made appeals to the national party to target Jackson, Jr.
As recently as last week, Jackson and his wife Sandi, the 7th Ward alderman, expressed interest in running for mayor of Chicago.
Tuesday morning, another possible mayoral candidate, Congressman Danny Davis, dismissed Jackson, Jr. as a contender.
"I don't think that he could run in this climate," said Davis.
Also in this atmosphere, Jesse Jackson, Jr. appeared together Tuesday night at her birthday party.
The press was asked to leave shortly after the two walked in the door. They arrived at the party without comment, joining 200-300 guests at the party. Many guests were high-profile politicians. Virtually all of them had read or heard about the Sun-Times report.
"I look at myself as going in to support a friend," said Democratic nominee for state treasurer Robin Kelly before she entered the party.
"Hopefully all the allegations will be cleared up," said comedian Damon Williams. "I'm a supporter of the Jacksons and I hope this thing works itself out."
Beyond a handshake and hello inside the party, Jackson, Jr. would not comment Tuesday night.
"Well, you know the Jackson family has a strong backbone, he's come from excellent pedigree," said State Sen. Rickey Hendon (D-Chicago). "They'll weather the storm."
During the period when the media was still allowed in the room, the Jacksons could be seen smiling, but the atmosphere in the room Tuesday night remained markedly tense.