Idaho Code § 74-407: TAX-RELATED correspondence.

(1) Neither the name of any elected public official nor any electioneering message shall appear on tax-related correspondence from the state of Idaho to a taxpayer, whether or not it includes a check, warrant, or rebate, or on county tax-related correspondence with a taxpayer, whether or not it includes a check, warrant, or rebate, unless acting as an endorser of a check, warrant, or rebate or unless otherwise necessary for the proper execution of a check, warrant, or rebate. This provision shall not apply to standard letterhead of the state or of a county.

(2) For the purposes of this section, "electioneering message" shall include statements regarding, expressing support for, or soliciting support for any:

(a) Governmental program or initiative; or

(b) Nonprofit corporation, including any program or initiative of a nonprofit corporation.