The bill would extend the waiting period to have an abortion from 24 to 72 hours after consultation with a physician. Twenty-six states require a woman to wait between receiving a consultation and having the abortion performed. Utah and South Dakota are the only states in the U.S. to have a 72 hour waiting period.
In his July 2 veto letter, Gov. Nixon cited the health of a woman as one of his main reasons for vetoing the bill.
"Lengthening the mandated delay is in contravention of sound medical advice and forces government even further into the relationship between the physician an the woman. A woman's health could be unnecessarily jeopardized by extending the mandatory delay," Gov. Nixon stated in his letter of veto.
In May of 2014, the Senate dismissed amendments that would allow a woman to forgo the lengthened wait time if her pregnancy was due to a rape or incest.
"This glaring omission is wholly insensitive to women who find themselves in horrific circumstances, and demonstrates a callous disregard for their wellbeing. It victimizes these women by prolonging their grief and their nightmare," Nixon wrote in his veto letter.
House Speaker Tim Jones, R-St. Louis County, called an override a "definite possibility" and said it will likely occur.
"Missouri continues to be a state that very much is on the side of being pro-child, of being pro-life, of promoting life, of standing up to life and I think that is a tact we will continue to pursue," Jones said.
The legislature can override the governor's veto with a two-thirds vote in both the House and Senate. The House passed the measure with a couple votes beyond a two-thirds vote. The Senate fell one vote short of a two-thirds, but an absent GOP senator -- Sen. Mike Cunningham, R-Rogersville -- said he will vote to override.
Missouri Right to Life, an anti-abortion organization, argues the governor's veto should be overridden.
"House bill 1307 is a very good bill," said Susan Klein, legislative liaison for Missouri Right to Life. "It gives women a chance to think about what they're about to do when they walk into an abortion clinic. They will be able to come out and spend the next three days really contemplating the decision on whether to take the life of their baby or not."
The executive director of Missouri NARAL, an abortion-rights organization, said the Nixon was courageous in his action to veto the bill.
"Women are smart enough to have made up their minds, women already have made up their minds before they receive abortion care and women can be trusted to make that decision for themselves without the intrusion of the state legislature," Pamela Sumners said. "We want Missourians to stand with Governor Jay Nixon because he has really brought great credit to the state with what he did in a time when the Supreme Court isn't doing us many favors and when our legislature certainly isn't doing us any favors."