The oldest living former U.S. senator turns 100 Thursday. James L. Buckley is among the few in American history who have served in the upper echelons of all three branches of our government. Jim Buckley served as a lieutenant in the Navy during the final years of the Pacific war. After the war, he attended Yale Law School and became an attorney. In 1970 Mr. Buckley won a historic third-party victory as the Conservative Party’s Senate nominee in New York. Serving as a U.S. senator until 1977, Mr. Buckley was an articulate and cordial agent of change and an advocate...