With a veto of a proposal to upend school teacher tenure rules, Gov. Mark Dayton wiped out one of Republicans top priorities Thursday.

The governor said the measure was an example of "prejudice against public school teachers" and singled out hard-working teachers by negating long-establishing bargaining rights and replacing them "with only vaguely formulated ideas."

The veto heightens the tension between the DFL governor and Republican Legislature. Last year, the budget chasm between them brought the state to a historic government shutdown and this year has left them unable to bridge philosophical gaps on multiple issues.

The education measure would have ended the "last in, first out" seniority-based system of layoffs for public school teachers, a basic tenet of union contracts, and allowed schools to consider other issues, like teacher effectiveness.

"The Governor has dealt a major blow to teachers, schools, students and parents across the state," said the chief sponsor of the proposal, Rep. Branden Peterson, R-Andover. Peterson and other supporters met with Dayton repeatedly to urge his signature on the bill to no avail.

"I am sorry that Governor Dayton chose to side with big labor special interests and sell out our children's futures," Peterson said.

The measure, which moved through the Legislature with almost no Democratic votes, had support from outside the Capitol and from groups with heavy lobbying forces at the Capitol. But it also raised the ire of union groups, particularly the powerful Education Minnesota teachers union.

In his veto, Dayton said that the Republicans were trying to move too quickly without allowing new teacher evaluation systems to even be developed. He said that after those measure are done, in 2015 or 2016, it would be appropriate for the Legislature to figure out how to incorporate them into lay off decisions.

Here's Dayton's veto letter:

Ch 274 HF1870 Veto-Attach

The bill vetoed by Governor Dayton would have allowed school districts the choice to consider a teacher's subject matter, licensure fields and their effectiveness, in addition to their seniority, when facing personnel decisions.