We Americans like to think of ourselves as enlightened in so many ways. As a nation, we're wealthier, healthier and better-educated than most of the world. Compared to many regions of the globe, the Middle East in particular, we are tolerant of most religions, ethnicities and life circumstances.

Take, for example, our approach to the disabled. In 1990, Congress passed the Americans with Disabilities Act, a wide-ranging civil rights law that prohibits discrimination against those with serious limitations of various types. Passage of the act was probably the crowning achievement of George H.W. Bush's presidency.

Many of us would like to think of the codified protections it afforded as an example to the world. And, in fact, it is. Yet, somehow, given the opportunity to endorse similar protections for the disabled citizens of all nations, the U.S. Senate failed Tuesday, voting down ratification of the United Nations Convention on the Rights of Persons With Disabilities. That treaty simply declares that all people, regardless of ability or disability, have the right to live in dignity, safety and equality under the law. Some 125 countries have signed it, and the Senate Foreign Relations Committee approved it last July in a bipartisan vote -- adding, presumably to quell fears of a fantasy One World Government, that by signing the pact, the U.S. relinquishes zero sovereignty.

But then, despite an emotional, last-minute plea for passage from former Sen. Bob Dole, 89, who rolled into the chamber in a wheelchair, still convalescing following a stay at Walter Reed hospital, the effort fell five votes short of the 66 needed for supermajority ratification.

How? Why? Because too many senators read phrases like "reproductive health" and "family planning" and see only one thing: abortion. Those concepts are mentioned in the treaty only because it extends all rights to the disabled that are available to the abled of a given nation. Otherwise, the treaty is in no way "about" abortion or reproductive health.

Senators can, should and will vote their consciences when it comes to abortion, but they would have done well to consider this: The U.S. already has statutes on the books banning American aid for abortion services in other countries. This U.N. treaty would have in no way changed that.

Abortion politics is dicey business in the U.S., of course. Republican senators who are up for re-election in 2014 and are potentially vulnerable to primary challenges from the right -- including people like Saxby Chambliss, Lamar Alexander and Mitch McConnell -- apparently can't risk even the most innocuous vote once the faintest whiff of the "a" word has wafted through the room.

So hysteria and domestic politics prevail. The world's disabled will just have to get their assurances of equal treatment elsewhere -- and from countries other than the one that enshrined the concept that all men are created equal.