Democratic Gov. Janet Napolitano on Monday vetoed a private school voucher bill that Republican supporters didn't expect to become law.

Besides launching a voucher program for children from low-income families, the bill vetoed by Napolitano would have provided dollars she wanted to expand all-day kindergarten and created a new tax credit sought by Republicans for companies' donations to private school tuition groups.

In a brief letter explaining her veto of the bill (HB2782), Napolitano noted that she has steadfastly opposed vouchers "as they fail to further educational opportunities for all Arizona students."

The Republican-led Legislature passed the voucher bill Friday though GOP leaders and Napolitano had agreed Thursday on a budget package that included the kindergarten funding and the tax credit but not vouchers.

Senate President Ken Bennett, R-Prescott, said Friday that Republicans sent the three-part bill to Napolitano anyway as a political statement to demonstrate Republicans' support for vouchers and Napolitano's opposition.