There may be added to a union's political fund only—
sums representing contributions made to the fund by members of the union or by any person other than the union itself, and
property which accrues to the fund in the course of administering the assets of the fund.
The rules of the union shall not be taken to require any member to contribute to the political fund at a time when there is no political resolution in force in relation to the union.
No liability of a union's political fund shall be discharged out of any other fund of the union.