Gov. Janet Napolitano's vetoes are about to put her in the Arizona history books again.

A year after setting a single-session record for Arizona governors with 58 vetoes — Republican Jane Hull set the old record of 28 in 2001 — the first-term Democrat is poised to capture the all-time record.

So far this year, Napolitano has rejected 31 bills passed by the GOP-majority Legislature, including measures that would have created a new tax break on companies' donations for private school scholarships and would have tightened an existing law requiring parental consent for minors to have abortions.

Her record veto — No. 115 — could come Monday, when she is expected to act on a wide-ranging border security bill. It includes provisions similar to a bill she previously vetoed that would have made illegal immigrants' presence in Arizona a crime under the state's trespassing law.

Napolitano refused to say if she will veto the measure, but she warned legislative leaders she would if the bill included criminalization provisions.

The Legislature has not yet been able to override one of her vetoes.

Her most recent veto on May 16 — rejecting a bill to impose new restrictions on cities' use of impact fees charged for new developments — tied her with fellow Democrat Bruce Babbitt, according to figures compiled by the Arizona Capitol Times newspaper.

However, Babbitt cast his 114 vetoes in just under nine years in office, while Napolitano has yet to finish the four-year term she began in 2003.

Napolitano is running for re-election this year. She enjoys strong poll ratings, and several prominent Republicans decided against challenging her.

Political insiders say Napolitano's veto tally reflects her political self-confidence, the fact that she and most legislators belong to different parties and Republican lawmakers' willingness to pass bills even though they're likely to be vetoed.

"This governor has absolutely no reservation about putting her mark on anything," said Republican lobbyist Kevin DeMenna, a former Senate chief of staff. "A lot of times legislation is laid on the governor's desk to send a message — perhaps in some cases (that is) even the primary motive — but this governor has not shied away in responding."

Napolitano said she hadn't paid attention to the imminent veto record and doesn't weigh public-opinion polling results when deciding whether to veto a bill.

She said last week she bases her decisions on whether a bill makes sense, accomplishes its purpose and is well-written.

"Some vetoes are vetoes because it's a matter of principle but some are because there simply has been inadequate communication between the Legislature and the executive," Napolitano said.

Political insiders said several circumstances help punch up Napolitano's veto tally.

Like Babbitt, "you have an activist Democratic governor and a real conservative House and Senate," said Barry Aarons, a Republican lobbyist who served two stints in the 1990s administration of GOP Gov. Fife Symington.

Also, Aarons said, "the Legislature has a feeling that it needs to establish a philosophical position to respond to the constituency that it represents."

Aarons said that in previous administrations legislative leaders were willing to move on and change the subject after a veto.

The current leadership doesn't do that, he said.

In 2005, Napolitano vetoed a Republican plan to bolster programs for students learning English. Lawmakers sent her two more versions this year, and she vetoed both. She finally let another version become law without her signature expecting that a federal judge would rule it inadequate — and he did.