An exchange at the end of Thursday night’s vice-presi­den­tial debate illustrated the complex — and, at times, difficult-to-reconcile — positions taken by the Republican ticket on the issue of abortion.

Moderator Martha Raddatz asked Rep. Paul Ryan (Wis.), the GOP vice-presidential nominee, how a Mitt Romney administration would handle that issue: “Should those who believe that abortion should remain legal be worried?”

Ryan replied: “We don’t think that unelected judges should make this decision.” He seemed to mean the U.S. Supreme Court, which legalized abortion with its 1973 decision in Roe v. Wade. Instead, Ryan said, the issue should be settled by elected officials, and “the democratic process.”

But just days before, Romney had told Iowa’s Des Moines Register that — if elected — he did not anticipate pushing antiabortion measures. “There’s no legislation with regards to abortion that I’m familiar with that would become part of my agenda,” Romney said.

Romney’s campaign then issued a statement walking back the candidate’s words: “Gov. Romney would of course support legislation aimed at providing greater protections for life,” spokeswoman Andrea Saul said.

What Romney said then and what Ryan said Thursday are not necessarily in conflict. In both cases, the federal government — including the Supreme Court and Congress — could leave abortion laws up to individual states.

Romney’s Web site says this would require the Supreme Court to first overturn Roe v. Wade. Then “states will be empowered through the democratic process to determine their own abortion laws and not have them dictated by judicial mandate.”

After the debate, Ryan’s argument was praised by the Susan B. Anthony List, an anti­abortion political group.

“Tonight, Congressman Ryan explained the pro-life position with clarity and candor,” Marjorie Dannenfelser, the group’s president, said in a statement. “The Romney-Ryan ticket is clearly committed to protecting American women and unborn children — as well as our conscience rights and religious freedom.”

But the position Ryan articulated Thursday — “the policy of a Romney administration will be to oppose abortions with the exceptions for rape, incest and life of the mother” — is different from Ryan’s earlier position of no abortions, except possibly in cases where mother’s life was endangered.

Still, his response was enough to provoke anger from groups that support abortion rights.

“He refused to say whether American women should be worried about the future of their reproductive freedoms if he and Gov. Romney win the White House,” Nancy Keenan, president of NARAL Pro-Choice America, said in a statement. “Let me be clear: The Romney-Ryan ticket is extremely dangerous to women’s health.”

After Ryan’s answer, Vice President Biden used a tactic that came up more than once in the debate: He spoke directly to viewers and asked whether they trusted his side or the other more on this issue.

He mentioned Robert Bork, a conservative jurist who was rejected as a nominee for the Supreme Court in the 1980s.

“Just ask yourself, with Robert Bork being the chief adviser on the court for — for Mr. Romney, who do you think he’s likely to appoint? Do you think he’s likely to appoint someone like Scalia or someone else on the court far right that would outlaw — outlaw abortion?” Biden said.

He mentioned, though not by name, Obama’s appointment of two justices, Sonia Sotomayor and Elena Kagan. “I guarantee you, that will not happen. We picked two people. We pick people who are open-minded. They’ve been good justices. So keep an eye on the Supreme Court.”

This story was updated to correct Rep. Ryan’s previous position that would have permitted abortions in cases where the mother’s life was in danger.