Now I appreciate Cal State's desire to follow the law; the California Constitution does prescribe the text of the oath, and says "all public ... employees, ... except such inferior officers and employees as may be by law exempted, shall, before they enter upon the duties of their respective offices, take and subscribe the following oath or affirmation." But surely there are times to interpret laws as requiring substantial compliance rather than strict literalism. Even the precedent that Cal State's Human Resources director JoAnne Hill cites as supposedly requiring the exact text of the oath (see the article for more on that) seems to take this view: It rejected the applicant's modified oath only after stressing that the modifications were not "surplusage" or "innocuous or merely expository," but rather "ma[d]e equivocal the essential oath preceding [the applicant's personal statement]." Likewise, the venerable principle that laws should be interpreted in a way that minimizes possible constitutional problems (here chiefly First Amendment problems related to compelled speech) counsels in favor of reading the law to provide some flexibility. In light of this, letting Marianne Kearney-Brown sign the entire oath, simply with the addition of a term, seems sufficiently consistent with the state mandate.
True, the Supreme Court has held that it doesn't violate the First Amendment to require certain narrow loyalty oaths, including support-and-defend oaths, for government employees. But the Court's justification was precisely that these oaths "do[] not require specific action in some hypothetical or actual situation"; they embody "simply a commitment to abide by our constitutional system ... [and] a commitment not to use illegal and constitutionally unprotected force to change the constitutional system."