Friday is the 15th anniversary of the day the Americans with Disabilities Act went into effect. Since then, a barrage of legal challenges has rendered the ADA much weaker than envisioned.

Title I, which prohibits employment discrimination, has especially taken a hit over the years. Employers from both the public and private sectors have frequently challenged the ADA’s definition of disability and have narrowed the scope of who qualifies for protection under the law. It is now at the point where people with such conditions as diabetes, heart disease, cancer and significant vision loss have had their cases dismissed because judges determined they don’t qualify as disabilities.

Employment discrimination suits brought under the ADA are rarely successful in courts. Every year since 1992, the American Bar Association has surveyed Title I cases, and each year the survey reveals that employers have prevailed in more than 90 percent of the decisions.

President Bush has helped undermine the law his father proudly signed by appointing active opponents of the ADA to the federal bench.

In the infamous University of Alabama v. Garrett case in 2001, William Pryor, who was then attorney general of that state, hired Jeffrey Sutton to argue before the U.S. Supreme Court that state governments should be immune from Title I lawsuits brought forth by state employees. Sutton and Pryor won. Bush subsequently placed both men on the federal bench.

In spite of the setbacks, America is vastly more accessible than it was 15 years ago. We have the ADA to thank for that. What made this law revolutionary was that it extended the obligation not to discriminate to the private sector. As a result, sometimes the mere threat of legal action has brought about positive change for people with disabilities.