DENVER - Whether the state constitution should define life as beginning at fertilization will be up to Colorado voters in November.

And unlike other ballot initiatives, it appears it will head to the ballot without having to go through the courts.

The Secretary of State's Office on Thursday certified that Peyton resident Kristi Burton collected more than enough signatures to put her Personhood Amendment to a statewide vote.

The newly renamed Amendment 48, which opponents fear could be used to ban abortions and is likely to make Colorado a national battleground, is the third citizens initiative to qualify for the ballot this year.

As Burton celebrated, opponents of the second approved initiative, Amendment 47, sued the state to pull the measure ending mandatory union dues from the ballot.

They claimed the petitioning was tainted by a "massive and pervasive pattern of fraud at every step of the process." The lawsuit came a month after activists floated the same accusations against the anti-affirmative action Amendment 46 and sued to remove it from the ballot.

Protect Families Protect Choices Coalition spokeswoman Crystal Clinkenbeard said Thursday the organization doesn't plan to sue over Amendment 48, Instead, it will work to defeat it at the polls, she said.

Burton already has had to win one legal challenge - over whether her amendment dealt with only one subject, as state law requires.

That and the two lawsuits over the other proposals are a sign of an emerging political strategy - courtrooms over courting voters.

"It's a very expensive proposition to beat back any amendment to the constitution in an election," noted Craig Hughes, spokesman for the "Vote No on 46" campaign.

Amendment 46 survived a lawsuit last year in which opponents claimed the measure, which ends race-based preference programs in public colleges and workplaces, of violating the state's single-subject ballot-title rule.

Opponents returned to court, saying some petitioners lied to signers about its intent and that some petition circulators were not state residents. No trial date on whether it should be removed from the ballot has been set yet.

The Amendment 47 challenge filed late Wednesday is similar, with the union-led Protect Colorado's Future group noting that some home addresses listed by petition circulators include a payday loan store, a vacant storefront and an empty field. Circulators also allowed some people to sign multiple times, executive director Jess Knox alleged.

Kelly Harp, spokesman for the group supporting the amendment, said opponents just don't want voters deciding public-policy issues. He echoed words of Amendment 46 supporters when he called the lawsuit a "smokescreen" to try to stop a vote on a measure that will pass in November.

Colorado AFL-CIO Executive Director Mike Cerbo, whose organization is part of Protect Colorado's Future, said the new wave of lawsuits don't represent political maneuvers so much as an increased vigilance of a petitioning process that had gone relatively unchecked in the past.

With several dozen petitions still circulating on other subjects, it is likely that more legal challenges may be filed, Colorado State University political science professor John Straayer said.