RULES FOR COUNTING VOTES NOT CAST FOR BOTH CANDIDATES.
Tex. ELEC Code § 192.037.
in effect(a) If a voter writes in the name of a write-in candidate for president or vice-president but does not write in a name for a running mate, the vote shall be counted as a vote for the candidate and the candidate's running mate.
(b) A vote shall be counted for both candidates of a set of candidates for president and vice-president if:
(1) the ballot is marked to indicate that the voter is voting for one of the two candidates;
(2) the ballot is marked to indicate that the voter is not voting for the other candidate in the set; and
(3) the voter has not:
(A) indicated a vote for a presidential or vice-presidential candidate of another set; or
(B) written in the name of a person for whom the voter desires to vote instead of the candidate for whom the voter is not voting under Subdivision (2).
(c) The secretary of state shall prescribe guidelines consistent with this code to assist counting officers in counting ballots in which the presidential race is irregularly marked.
SUBCHAPTER C. WITHDRAWAL, DEATH, AND INELIGIBILITY OF PRESIDENTIAL AND VICE-PRESIDENTIAL CANDIDATES; CERTIFICATION OF INABILITY TO SERVE