The Capitol (J. Scott Applewhite/AP) The Capitol (J. Scott Applewhite/AP)

If you  haven’t already read Nate Cohn’s excellent story in the New York Times on the potential power of the black vote in this November’s midterm elections, you should. He makes the same prediction I have been making for months now. “If Democrats hold the Senate,” he writes, “they will do so because of Southern black voters.” But my forecast is always tempered by the fact that African American voters, like most voters, stay home in non-presidential election years. Cohn gives me a little more hope that this time will be different.

“The trends increasing the clout of black voters reflect a complete cycle of generational replacement in the post-Jim Crow era,” Cohn notes. “White voters who came of age as loyal Democrats have largely died off, while the vast majority of black voters have been able to vote for their entire adult lives — and many have developed the habit of doing so.”

When it comes to the Senate map, the toughest and closest races Democrats face are in southern states. As The Post’s Aaron Blake reported in April, “Six of the 16 states with the highest black populations are holding key Senate contests in 2014.” Three of those states — Louisiana, North Carolina and Arkansas — “are widely considered to be the most pivotal when it comes to the GOP’s hopes of winning the majority.” Cohn adds Georgia to the list. “Black voters will most likely represent more than half of all Democratic voters in Louisiana and Georgia, and nearly half in North Carolina.”

Michelle Nunn (Erik S. Lesser/EPA) Michelle Nunn (Erik S. Lesser/EPA)

In addition to “the collapse in Southern white support,” Cohn says a major factor in black voter power in the south is the re-migration of African Americans to the region. And Cohn writes that this could benefit Democrats in November, particularly in Georgia where Michelle Nunn is seeking election to the open Senate seat there. “Since 2000, as the black population has risen, the share of registered voters who are white has dropped to 59 percent, from 72 percent,” he reports. “The state’s growing black population will give [Nunn] a chance to win with less than one-third of the white vote, a tally that would have ensured defeat for Democrats just a few years ago.”

We know what happens when African Americans show up at the polls. President Obama got elected twice. Gov. Terry McAuliffe took over Virginia. Sen. Thad Cochran (R-Miss.) survived a tea party challenge. All they have to do is show up in November with the same vigor they did in those races in order to add a continued Democratic majority in the Senate to their win column. Cohn makes a convincing case for why it is not as tall an order as I think it is.

Follow Jonathan on Twitter: @Capehartj