The newest senator is South Carolina Rep. Tim Scott, whom Gov. Nikki Haley said she would appoint to fill the vacancy caused by the pending resignation of Jim DeMint.
The most senior senator was Hawaii's Daniel Inouye, who died at 88 just a few hours after Haley's announcement.
Much has been made of the fact that Scott will be the only black senator and the first black Republican senator since Edward Brooke of Massachusetts, who was elected in 1966 and 1978.
Haley noted that fact and made the point that he was qualified on the merits. He has served only one term in the House, but that's also true of his South Carolina House Republican colleagues except one, who asked that he not be considered for the seat.
Scott also served a term in the South Carolina House and for 13 years on the Charleston County Council. He built a real estate and insurance business in Charleston with both black and white clients. That seems like a good set of experiences to bring to the Senate.
Daniel Inouye started serving his country long before Tim Scott was born. As a teenager, he saw the Japanese bombers over Pearl Harbor and was one of the Japanese-Americans who volunteered for the 442nd Regimental Combat Team, the most decorated Army unit in history.
He lost an arm in combat in Italy in April 1945, less than a month before Germany surrendered, and in the army hospital met Bob Dole, whose arm was shattered the same month.
Inouye was elected Hawaii's first congressman when it was admitted to the Union in 1959, the first Japanese-American member of Congress. He won his Senate seat in 1962 and died 17 days short of serving 50 years.
Most Americans today would find it hard to imagine the degree of anti-Asian prejudice in the early years of his career. Inouye attended a segregated public school, and U.S. immigration laws effectively barred Asians from entry.
Japanese-Americans on the West Coast were rounded up and placed in internment camps. Such things were largely taken for granted and widely approved.
In contrast, today one has to look very hard for signs of anti-Asian animus in American life. The only significant discrimination practiced against people of Asian descent is by admissions officers at selective colleges and universities, who worry about an Asian "tilt" because so many have sterling high school records.
Such a change in attitudes took a generation or so. It has been so thorough that most of us don't realize that it occurred.
The appointment of Tim Scott reminds us that there has been an enormous change in non-black Americans' attitudes toward blacks, as well.