It's not every day that Congress marks the anniversary of a 20-year-old law. And it's even less frequent that the same anniversary is celebrated by the administration and public policy advocates, too. But this week was an exception.

Twenty years ago this week, on February 5, 1993, President Clinton signed the Family and Medical Leave Act into law. The FMLA, which mandates that employers with 50 or more workers provide up to 12 weeks of unpaid leave to workers who need to care for themselves or a family member with a serious illness, or after the birth or adoption of a child, has undoubtedly altered the employment law landscape over two decades.

The anniversary was celebrated on Capitol Hill by lawmakers and by the National Partnership for Women and Families, which helped draft the law. While the bill was signed in 1993, it was first introduced in Congress in 1985, and survived two presidential vetoes before finally being enacted.

The FMLA "was the first piece of legislation that said, the lives of the families of this nation have changed, and our public policy has got to change with it," Rep. Rosa DeLauro (D-Conn.) said Feb. 4. The law "transformed American workplaces for the better," she said, making them "more family friendly and more productive."

Meanwhile, the Labor Department held an event this week to observe the anniversary, and also to issue a final rule that extended the provisions of the FMLA to airline flight crews and the families of veterans. Previously, because of the way some airline workers' hours were calculated, they failed to qualify for leave under the law.

Work and family advocates used the anniversary to press for expansion of FMLA provisions to cover more people, and to require employers to provide paid leave.

For example, Sen. Tom Harkin wrote an op-ed for Politico about sick leave policy, and said he would again introduce the Healthy Families Act, which would require employers to provide paid sick days to workers.

Debra Ness, the president of NPWF, in a statement said her group "intended the FMLA to be the first step on the road to a family friendly nation." Now, she said, "we are asking Congress to expand the law so more workers can take leave for more reasons, and to adopt a national paid family and medical leave program."

Harkin also spoke about leave policy on the Senate floor.

"A social insurance program to provide some wage replacement during family and medical leave would allow families to maintain their economic security while seeing to their families," he said. "Research shows that this could be done on a universal basis with very small, shared contributions by workers and their employers. Two states, New Jersey and California, have already implemented such paid leave systems, helping families in those states to be financially secure during family and medical leave."

Any paid leave measure introduced in Congress today would face a tough road, especially in the Republican-controlled House. But given the celebrations of FMLA on Capitol Hill this week, paid leave supporters don't appear to be slowing down.

It did, after all, take eight years for that bill, which Harkin said "has changed this country in profoundly important ways," to become law.