Ben Carson warned against the growing power of the federal government and "baby killers" denying the humanity of fetuses during his keynote speech at the 2015 National Right to Life Conference in New Orleans.

"When I look there in particular out to the next generations. As we destroy them economically as we destroy them morally as we weaken our defenses as we do all the things that are necessary to bring down our nation," Carson said.

Carson's comments about government overreach came in reaction to the Supreme Court's recent decision upholding Obamacare subsidies for federal exchange customers. Carson said "the Affordable Care Act is the government saying we don't care what we the people think."

But Carson, a famed pediatric neurosurgeon, reserved his harshest criticism for people who support legal abortion. He said there are people who go to "great lengths to save spiders" but not fetuses between six and 10 weeks old.

"The baby killers, that's what they do, manipulate you into thinking this is not a human being," Carson said, adding they "capitalize on people's lack of knowledge." He added that technology was making more people pro-life, because ultrasounds showed them the truth about fetal development.

Many people in attendance at the National Right to Life Conference were evangelicals, a large bloc of voters to which Carson appeals. Carson called on them to speak up for their values.

"I think it's us the American people who will make the difference," Carson said. "It was Thomas Jefferson said this would happen. That we would become relaxed, and that the government would grow and it would infiltrate every aspect of our lives. But just before we turn into another form of government he said the people would waken and reassert themselves. I think now is the time we must do that if we are to save our nation."

In the last election, 30 million evangelicals did not vote, Carson claimed. He urged attendees to encourage their friends to go to the poll, saying "our strength is in unity and belief system."