Colorado voters are weighing whether to approve a first-in-the-nation "personhood" law, which would extend legal rights to the unborn in a move critics say could effectively ban abortions. 

The measure, called Amendment 67, would have far-reaching consequences in the state, changing the Colorado constitution to protect "pregnant women and unborn children by defining 'person' and 'child' in the Colorado Criminal Code and the Colorado Wrongful Death Act to include unborn human beings." 

Political analyst Eric Sonderman notes this is not the first time the "personhood" question has been on the Colorado ballot. "It's gone down to overwhelming defeat on past occasions," he said. 

Similar attempts in other states also have failed. 

This time in Colorado, though, supporters have tied the measure to a tragic accident in July 2012. Heather Surovik was eight months pregnant and on her way back from a prenatal visit when her car was struck by a drunk driver. 

"When she woke up in the hospital, she was told that her baby had not survived," Amendment 67 backer Jennifer Mason recalled. "But not only that, there would be no charges filed in relation to his death because under Colorado law, he was not considered a person." 

Heather Surovik said, "They can't tell me that's not a baby. He was eight pounds, two ounces. Brady was the second victim, and nobody recognized it." 

Fofi Mendez, campaign manager of "Vote NO 67," sympathizes with Heather Surovik's loss but warns that redefining the words "person" and "child" to include the unborn would have the effect of banning all abortions, and even some forms of birth control. 

"You end up giving legal and constitutional rights to a woman's fertilized egg and when you apply that definition to the criminal code and the wrongful death statute, you end up making criminals out of women and their doctors," Mendez said. 

When asked if doctors should be concerned that they would be committing a crime for performing abortions if Amendment 67 passes, Mason said: "Well, they could be. If an unborn child is a person and we recognize that they are a person, should we say that some children should be protected and some shouldn't?" 

Opponents also point out that in 2013, legislation inspired by Surovik's case was signed into law that criminalized the unlawful termination of a pregnancy. If the same accident happened today, the drunk driver who crashed into Surovik's car would be charged for the loss of her unborn child. 

Even if Amendment 67 does not pass -- and recent polls suggest it probably won't -- the biggest impact of its presence on this year's midterm ballot could be on the U.S. Senate race between incumbent Democratic Sen. Mark Udall and his challenger, U.S. Rep. Cory Gardner. The contest is one of the tightest and most-closely watched in the country. 

"If Cory Gardner ends up losing this Senate race, which is probably right now a flip of a coin," Sonderman said, "you might be able to track it back to one word, that word being personhood." 

Gardner supported personhood amendments in previous years that went down in defeat in Colorado. His support came while he represented one of Colorado's most conservative districts in the U.S. House. Gardner, who now is running statewide in this very purple state, announced early in the race that he will not support Amendment 67. 

He is taking hits from both sides for his decision. "I think that Cory Gardner has shown himself to be untrustworthy to the voters," Mason said.