The former congressman and his wife Sandi Jackson will be sentenced on July 3.
In papers filed in Federal Court in Washington, Jackson gets support from TV personality Tavis Smiley and powerhouse attorney Vernon Jordan.
Smiley said "Mr. Jackson's actions cannot be condoned, they are inconsistent with the character of the public servant that I have worked alongside for the betterment of our democracy."
A filing from Vernon Jordan reads: "Mr. Jackson's conduct was inexcusable, but his efforts on behalf of those less fortunate than himself should not be forgotten."
