In the winter of 1996, I was trying to craft a strategy to override then-President Bill Clinton's veto of the Partial Birth Abortion Ban Act.

In many respects, it was the nadir of the pro-life movement. Mario Cuomo's 1984 speech at Notre Dame had proven to be a winning formula for pro-choice politicians. The Catholic New York governor had famously said he was personally opposed to abortion, but would not impose his "values" on others who differ.

In Bill and Hillary Clinton, we had a president and a first lady whose abortion mantra, "safe, legal, and rare," had made even more Americans comfortable with the pro-choice position.

Up to this point, I had never waded into the abortion issue during my five years in Congress. But this bill banned abortions in which a baby who would otherwise be born alive is delivered, except for the head, and then killed.

The horror of the procedure shocked my conscience. I could no longer ignore the reality of abortion. I could no longer turn away.

I was not alone. Beginning in 1996, public attitudes on abortion began to change for the first time since the Supreme Court's 1973 ruling in Roe v. Wade. According to a Gallup Poll in 1995, pro-choicers outnumbered pro-lifers 56 percent to 33 percent. After high-profile but unsuccessful efforts to override Clinton's partial-birth vetoes in 1996 and 1997 - efforts that saw pro-choice lions such as Sens. Pat Moynihan and Arlen Specter vote to ban the procedure - the margin shrank to 48 percent pro-choice to 46 percent pro-life.

The margin over the next decade fluctuated within a 10-point spread, but Gallup never recorded a majority of Americans identifying themselves as pro-life - until now. This month's survey found the pro-life position favored, 51 percent to 42 percent.

What happened? Many things probably set the stage for the shift. Three- and four-dimensional ultrasounds showcase the humanity of a child in the womb in amazing detail. Claiming a fetus is just a "collection of cells" or "blob of tissue" just doesn't cut it anymore.

The hit movie Juno and rapper Nick Cannon's song "Can I Live?" - which thanks his mother for canceling the abortion that would have killed him - also have helped make the pro-life position more acceptable.

But what triggered the sharp moves in the pro-life direction in the late 1990s and this decade?

Look to the Oval Office. If Bill Clinton had ignored the National Abortion Rights Action League and other extremists and simply signed the partial-birth-abortion ban, the horror that shocked me and our nation would have been forgotten. But Clinton's defense of the indefensible - and the resulting battles with Congress - made for a story the press could not ignore.

Today, the shift is being furthered by President Obama's extreme record on the issue as well as Notre Dame's decision to honor him.

Obama's Notre Dame outing has brought his record to light and furthered the pro-life cause. Aside from his outrageous opposition to an Illinois Senate bill to protect infants who survive abortion attempts, there's his four-month record as president.

He has funded stem-cell research, which involves the taking of human life. His administration had considered removing some conscience-clause protections for health professionals who object to performing abortions or referring patients for them. The Food and Drug Administration has allowed the "morning-after pill" to be given to 17-year-olds without a doctor's prescription or parental consent.

Obama has provided taxpayer dollars for overseas abortions and promised to support the Freedom of Choice Act, which would repeal state and federal restrictions on abortion.

Obama's zealotry has helped move moderate Republicans into the pro-life camp. From 2001 through last year, 55 to 60 percent of Republicans said they were pro-life, while 33 to 38 percent identified themselves as pro-choice, according to Gallup. But the most recent poll shows that 70 percent of Republicans are now pro-life, while only 26 percent are pro-choice.

Even though they certainly had different motives, Clinton, Obama, and Notre Dame have all helped the pro-life cause.

E-mail Rick Santorum at rsantorum@phillynews.com.