A "torn" Gov. Mark Dayton has vetoed a bill that would have increased the minimum amount of custody awarded to some Minnesota parents by more than a month.

In one of its last acts before adjourning for the year, the Legislature passed a bill that would have rewritten the formula the state uses to award custody. It would have increased the presumed minimum amount of custody for either parent from 25 percent of the year to 35 percent, or an increase of about 37 days of parenting time.

The legislation was cheered by some parents -- particularly fathers -- who said the current formula makes it very difficult for them to build relationships with children they see only every other weekend, plus a few weeks over the summer.

"It's a terrible irony. You work so hard to be part of their lives when you have such limited time," said Brian Ulrich of St. Cloud, one of half a dozen fathers who held up protest signs outside the governor's office this week, urging him to sign the bill. "And they call you a Disney parent, because all you do is have fun. Well, that's because you [don't have a larger custody share]. You don't go to the school [conferences], you don't do the disciplining, because you aren't there."

But family court advocates say changing the custody formula isn't necessary and isn't a good idea.

"It focuses on parents' wishes, not children's needs," said family law attorney Michael Dittberner, an outspoken opponent of the bill. Most parents, he said, use the 25 percent formula as a baseline and work from there, but locking in a 35 percent minimum doesn't allow for special circumstances, such as custody of infants or special-needs children, or parents and children who live far apart or who have troubled relationships.

That's the argument that swayed the governor, who on Thursday allowed the bill to expire on his desk, unsigned.

"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 in a letter to the Legislature, explaining his decision.

The letter continued: "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 governor called on the Legislature to take the issue up again next year, to try to work out a compromise that would serve the best interests of both parents and children.

The governor's offer did not satisfy the group of fathers-rights protesters who had been keeping vigil outside his office this week, hoping that Dayton -- a divorced father himself -- might be more sympathetic to their cause.

"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 her 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 the 55th veto the governor has issued in the first two years of his term.

Jennifer Brooks • 651-925-5049