Governor Napolitano’s final veto of the session was no surprise, considering that the bill she killed, H2345, to require voters to show identification before casting ballots, was opposed by every Democrat in the Legislature.

“This bill, which would make voting more onerous for any citizen who fails to present verifiable identification at the polling site, is unnecessary and counter to the goal of increasing voter participation,” the governor wrote in her June 26 veto message.

It was Ms. Napolitano’s 17th veto. That’s good for ninth place overall among Arizona’s 21 governors since statehood and advances her to second place on the list that divides total vetoes by the number of regular legislative sessions held during a governor’s term.

This list, the “Session Year Average” (SYA) for lack of a catchier term, is a half-serious attempt to provide a clearer comparison of today’s veto-happy governors with the eight governors who served before 1951. Most vetoes are issued during regular sessions, and back then the Legislature met in regular session only every other year, so those governors didn’t have as much opportunity.* —

*Veto statistics are like baseball statistics: they’re good for an argument in any crowd of the faithful. With 17 vetoes (so far) in one year, Ms. Napolitano’s SYA is 17, closing in on Jane Dee Hull, who posted an SYA of 17.6 with 88 vetoes during a term that included five regular sessions. She vetoed more bills than any other governor except Bruce Babbitt, but he is only No. 4, his SYA a relatively mere 12.7 because he had nine session years to amass his all-time killer bag of 114. Ahead of Mr. Babbitt is a governor few remember today: Dan Garvey. He was governor when the Legislature met only every other year, and he had only one regular session of opportunity (it was 1949). He made the most of it with 16 vetoes.