Gov. Mark Dayton has vetoed the final bill of 2012, an attempt to change the child custody formula to guarantee parents more time with their children

"Both proponents and opponents make compelling arguments in support of their respective positions," Dayton wrote in a Thursday letter to the Legislature, after opting not to sign the custody bill, essentially issuing a pocket veto of the legislation.

Right now, Minnesota law presumes that both parents in a custody settlement will get a minimum amount of time -- 25 percent of the year -- with their child. The bill would have increased that minimum to 35 percent.

Supporters of the change said it would give non-custodial parents more quality time with a child than every other weekend and two weeks during the summer -- a breakdown that doesn't even equal 25 percent of the child's year. Opponents said the new formula took control away from courts and was designed to represent a parent's interest more than the child's.

In his letter to lawmakers, Dayton said there was too much uncertainty about how the change in the custody formula might affect children. But he urged lawmakers to take up debate on the issue again during the 2013 session.

"People and parties on both sides of the legislation share the same good faith intentions rooted in their shared desire to prescribe what will be best for every parent and, especially, every child ensnared in the painful dissolution of a marriage," Dayton wrote. "Torn between the persuasive arguments of both proponents and opponents of the legislation, I am particularly influenced by the strong opposition of so many organizations (although not all of their members), who work every day with the most challenging divorces and their effects on the well-being, and even the safety, of parents and children."

The news was a blow to supporters of the legislation, who have rallied at the Capitol several times this week, urging the governor to sign the bill.

"I'm a dad who has seen my desire to be involved in my daughter's life thwarted by the family court," said David Weiss of St. Paul, holding up a sign decorated with pictures of his now-16-year-old daughter. Weiss said he has been battling for more time with his daughter for the past 10 years. "It's reached a point where the best I can hope for is to have a relationship with my daughter after she turns 18. I'm here for the other dads now."

This is Dayton's 55th veto of the 2011-12 legislative session.

 Read the full letter here: