Rev. & Tax. Code, § 24434

(a) In the case of a taxpayer (other than a bank as defined in Section 23039) no deduction shall be allowed under Section 24347 or 24348 by reason of the worthlessness of any debt owed by a political party.

(b) (1) For purposes of subdivision (a), the term “political party” means any of the following:

(A) A political party.

(B) A national, state, or local committee of a political party.

(C) A committee, association, or organization which accepts contributions or makes expenditures for the purpose of influencing or attempting to influence the election of presidential or vice presidential electors or of any individual whose name is presented for election to any federal, state, or local elective public office, whether or not such individual is elected.

(2) For purposes of paragraph (1)(C), the term “contributions” includes a gift, subscription, loan, advance, or deposit, of money, or anything of value, and includes a contract, promise, or agreement to make a contribution, whether or not legally enforceable.

(3) For purposes of paragraph (1)(C), the term “expenditures” includes a payment, distribution, loan, advance, deposit, or gift, of money, or anything of value, and includes a contract, promise, or agreement to make an expenditure, whether or not legally enforceable.

(c) In the case of a taxpayer who uses an accrual method of accounting, subdivision (a) shall not apply to a debt which accrued as a receivable on a bona fide sale of goods or services in the ordinary course of a taxpayer’s trade or business if both of the following apply:

(1) For the taxable year in which the receivable accrued, more than 30 percent of all receivables which accrued in the ordinary course of the trades or businesses of the taxpayer were due from political parties.

(2) The taxpayer made substantial continuing efforts to collect on the debt.