Washington, DC (LifeNews.com) -- The Supreme Court's decision to uphold the federal ban on partial-birth abortions could pave the way to a ruling reversing the high court's 1973 decision in Roe v. Wade that toppled pro-life laws across the country. That's something pro-life advocates relish and pro-abortion activists fear.

The thought is that if the high court could reverse its 2000 decision on partial-birth abortion that it could change its mind on abortion itself as well.

Wednesday's ruling is the first major abortion case in which new Chief Justice John Roberts and Associate Justice Samuel Alito have ruled, perhaps giving a clue as to their views on Roe itself.

The pair might very well join Justices Antonin Scalia and Clarence Thomas and a fifth justice in the future who would form a five-judge group giving it the majority on the high court for the first time since the landmark 1973 case.

A fifth judge is needed because Justice Kennedy supports Roe despite his joining the majority in the partial-birth abortion case and writing the main opinion.

Abortion advocates sense the thread Roe v. Wade is hanging by and communicated their fears to supporters in emails sent out on Wednesday.

NARAL president Nancy Keenan worried that, with the partial-birth abortion decision, "the Supreme Court has not only supported an abortion ban with no exception for a woman's health, it has given the green light to the anti-choice movement's plan to outlaw abortion entirely."

The Feminists Majority Foundation agreed and told its membership, "Today's devastating 5-4 decision by the Bush-stacked Supreme Court is a historical decision on abortion and women's rights and is a direct assault on Roe v. Wade."

Pro-life advocates recognize this as well and Jay Sekulow, the head of the American Center for Law and Justice, told LifeNews.com the "decision represents an important shift in the ongoing battle to protect human life and represents a very significant pro-life victory in the abortion debate.”

Roberta Combs, the president of the Christian Coalition, was more direct.

"With today's Supreme Court decision, it is just a matter of time before the infamous Roe v. Wade decision in 1973 will also be struck down by the court," she said.

What happens to Roe remains to be seen but Susan B. Anthony List president Marjorie Dannenfelser expressed the hope of everyone on the pro-life side of the abortion debate.

“Since the 2006 election, those fighting on behalf of the lives of the unborn have felt beleaguered and discouraged, but today's decision sparks hope that this could be the beginning of the end of the Supreme Court's dictatorship on this issue," she said.