Bill and Hillary Clinton have received no public support over the "Pardongate" scandal.
No-one has come forward to defend the former president after he granted 140 pardons on his last day in office.
In an opinion poll, Americans now view Mr Clinton as negatively as at any time during his presidency.
Mrs Clinton is under scrutiny after her brother received a £250,000 pay-off for soliciting pardons from Mr Clinton.
Only weeks ago the new Senator from New York was being mooted as a possible presidential candidate in four years.
One Washington insider said: "She would struggle to be elected local dog catcher."
Terry McAuliffe, the Democratic Party chairman, who calls Mr Clinton his best friend, has found it difficult to defend him.
After the payments to Hillary's brother, Hugh Rodham, were disclosed, Mr McAuliffe condemned his actions as "absolutely wrong."
The House Government Reform Committee is sending a letter to the former president's half brother, Roger, asking him whether he was involved in any of the pardons.
Roger Clinton, a singer, got his own pardon for a 1985 drug charge. Roger Clinton was arrested this week on suspicion of drunken driving in Los Angeles.