Tenacity.

Over the years that the award was given, Senator Proxmire provided steady material for reporters and headline writers and made the nation laugh.

But he counted among his most significant accomplishments the government's 1986 approval of an international treaty outlawing genocide, for which he had delivered more than 3,000 speeches in the Senate over a 19-year period and which President Ronald Reagan finally signed into law in 1988. It took 40 years for the United States to join 97 other countries in a treaty outlawing genocide and it would not have done so were it not for Mr. Proxmire's tenacity.

For two decades he would deliver a speech in favor of the treaty every morning the Senate was in session.

From NYT