Yesterday, John Kerry was confirmed as the country’s 68th Secretary of State, by a vote of 94 to 3. The only Republicans to oppose his confirmation were Ted Cruz and John Cornyn of Texas, and James Inhofe of Oklahoma. This morning, wasting no time at all, Massachusetts Governor Deval Patrick announced Kerry’s replacement—William “Mo” Cowan, Patrick’s former chief of staff.

Cowan will hold seat until this summer, when voters will choose someone to serve out Kerry’s term (in the running, so far, are Rep. Ed Markey and Rep. Stephen Lynch). In the meantime, Cowan will be the eighth African American to serve in the United States Senate, and the sixth since Reconstruction. What’s more, this will be the first time in more than a century that two African Americans have served concurrently in the Senate.

It should be said that Cowen will also be the third African American appointed to serve in the Senate. So far, only three blacks in the post-Reconstruction period have been elected to the legislative body: Massachusetts Senator Edward Brooke, and Illinois senators Carol Mosely Braun and Barack Obama. This dearth of elected black senators has everything to do with the unusual circumstances of African American politicians, who — with few exceptions — have the wrong set of qualities for running statewide. They tend to be more liberal than the median voter, they tend to come from lower-income areas (thus limiting their ability to fundraise), and they tend to either reside in conservative states (most African Americans continue to live in the South) or in large states, where they face stiff competition for the highest offices.

The unfortunate fact is that, barring a huge change in the political composition of Southern states, African Americans will continue to be a rare presence in the Senate. After Massachusetts voters choose Kerry’s long-term replacement, the U.S. Senate will go back to having a single black member — South Carolina Republican Tim Scott — with few others on the horizon.

Jamelle Bouie is a staff writer at The American Prospect, where he writes a blog.