Dubuque, IA (LifeNews.com) -- Sam Brownback continued to press the pro-life themes of his Republican presidential campaign in a stop in Iowa on Thursday. The Kansas senator said abortion is the greatest moral issue in politics and shared the story of his adoptive daughters with the crowd of 100 people at Loras College.

Brownback discussed his "pro-life, whole life" theme that includes protecting people both born and unborn.

"This is the biggest moral issue of the day," he said, referring to abortion. "We've killed over 40 million people that should be here."

The senator also discussed his two adoptive children and how they came from nations where abortion and infanticide have targeted girl babies.

He also said the women who have had abortions and regret their decision have the greatest chance to break the gridlock over abortion in the U.S. and persuade more people to support the pro-life position.

"With every abortion there's at least two victims. One dead, one wounded," he said. "We believe all people are sacred and they're beautiful."

He also said he was confident that the work of pro-life groups in changing hearts and minds would eventually win the abortion debate.

"We can get this done here. Once we win this fight, it will reverberate around the world," he said, according to the Tribune Herald newspaper.

Once abortion is made illegal in the United States again, Brownback said, it would impact the worldwide abortion debate and help places like Russia and Japan, where abortion has left the nations with underpopulation problems.

"This isn't rocket science. But it is about sacred life," he said.

Brownback also said he backs a human life amendment to the Constitution but knows that isn't a political reality right now.