WASHINGTON -- "Be careful who you let in your house," admonished Nellie Gray, president of the March for Life. It led her into more than three decades of volunteer service.

In an interview with Catholic News Service in early January, Gray reflected on the 29 previous marches and the path that led her to leadership of the annual march, which marks the anniversary of the U.S. Supreme Court's Jan. 22, 1973, Roe vs. Wade and Doe vs. Bolton decisions on abortion.

Back in late 1973, a group of East Coast activists wanted to march in Washington on the first anniversary of the decisions that, according to Gray, "decriminalized, not legalized," abortion.

"They didn't have a place to meet. They were aware I was in Washington and it was one of the few addresses they knew (there)," she said. "So they met in my house. And that's how I became president of March for Life."

Formed as "a temporary ad hoc body," the original March for Life group also developed the rose as its official symbol, and determined that marchers should deliver them to members of Congress, Gray said. Responsibilities for the march were divided up: "Somebody doing busing. Somebody doing housing. Somebody doing fliers."

The 1974 march "was put together in less than three months," she said. "Word went out. Somehow. And the people ... came down in hundreds of buses, 20,000 people. It was a sunny day, 70 degrees. The buses came and parked on the west side of the Capitol, which you can't do these days. The first march was a circle of life, around and around and around the U.S. Capitol."

Then as the marchers were "packing up, closing down, we realized Congress wasn't going to do anything about it," Gray said. "We had marched, but nobody was talking about it. Nobody was ready to do anything. So we decided to do one more march. And now we're at No. 30."

Gray was a federal civil servant at that time and considering retirement.

"I hadn't thought about doing volunteer service," she admitted. Then, while preparing for the second march, she began drafting some life principles, to better express why people should come and march.

"I spread it out among our people" for feedback, she said. The march's leaders then spent a day in a motel conference room in New York, "drafting, re-drafting" and finalizing the principles.

The result was nine declarations expressing the march's ideals, designed to guide pro-life Americans "in what kind of legislation we will and will not support," Gray said. "Those principles must guide us, not just in the March for Life, but in our individual lives and for our country," she added.

Primary among the principles, she said, is "When there is any doubt that there exists a human being's life to preserve and protect, such doubt shall be resolved in favor of the existence of a human being."

"At that meeting ... nobody wanted to be in charge of money or anything like that," she said. "So we decided to incorporate. I became the president. And that's the way it's been for 30 years."

She credited the Catholic Church with being at the forefront of the right-to-life movement in the early days.

"The church was already aware of the evils of abortion and what was happening in the United States because they had set up committees in various dioceses," said Gray, a Catholic. Even today, "the large majority of people who show up are from Roman Catholic dioceses and parishes. Or the Knights of Columbus or" the Ancient Order of Hibernians, an Irish Catholic organization.

Her most disappointing moment in the movement came after "very successful marches in 1979 and 1980," she said, when then-Gov. Ronald Reagan's staff sought pro-life grass-roots campaign support.

"The idea that we would have someone running for the U.S. presidency that would admit to a pro-life stance was extremely exciting. It seemed the right thing to do," she said. "He no sooner got in the White House than he began on the economy. And then (he) appointed Sandra Day O'Connor to the Supreme Court -- someone we already knew was for abortion.

"I became very politically aware at that moment," she said. "Candidates do indeed make promises. And when they get into office they do not carry out the promises they make."

But the march "has continued, not because of a lack of prudence, but because of determination and understanding," she said.

Although she said she wouldn't put marchers' lives in danger, any obstacles "absolutely pale in comparison to the devastation we feel in America from the intentional killing of pre-born children."

Gray wouldn't compare individual marches, though, choosing to emphasize the similarities.

"We look for steadiness," she said. "Steadiness in principles. Steadiness that we'll be here year after year after year. Steadiness that this is not going to be a celebration or a showpiece. ... We started this March for Life to stop abortion and that's what it is. The issue is exactly the same now as then."

Gray said the march offers "a vehicle for everybody to come together, no matter what their activity in the movement is."

"Crisis pregnancy centers, lobbyists, it doesn't make any difference what ... they come together," she said. "It is a constant reminder to Congress there are people who are not going away until Roe vs. Wade is overturned."