In the nearly 232-year history of the US Senate there have only been 11 Black senators

From slavery and Jim Crow laws to suppression of minority voters, Black political candidates have long faced stumbling blocks. Hiram Revels, the first Black US senator, took office in the late 1800s as part of a wave of African American lawmakers during the Reconstruction era, but he was elected by the Mississippi legislature, not the state's voters.

Decades of voter suppression has limited Black voting power in the South, says Tobin Miller Shearer, director of African-American studies at the university of Montana.

Shearer also cites the "incomplete legacy of the 15th Amendment," which granted everyone the right to vote but was undermined by states in the deep South which disfranchised Black voters through literacy tests, property ownership requirements and other racist measures.

It wasn't until 1965 that these discriminatory voting practices were outlawed by the federal Voting Rights Act.

Half a century later Black voters in the South are wielding new power, thanks in part to a push by former Georgia gubernatorial candidate Stacey Abrams and other organizers to register new voters and combat voter suppression.

"Black candidates can compete and win competitive statewide races if they are able to effectively mobilize the Black electorate," Hill says. "If the momentum created by Abrams and Warnock's recipe for mobilizing the Black electorate can be sustained, we could begin to see more Black representation in the US Senate. Only time will tell."

Here are the 11 Black US senators:

Hiram Revels was a former barber and minister who served in the US Senate from 1870-1871.

Mississippi lawmakers chose him to fill a vacant seat, although he faced fierce opposition from his future colleagues who questioned his citizenship. Their argument was based on a 1857 Supreme Court case that ruled African Americans could not become citizens of the United States.

Born a free man in 1827 -- the slavery era -- he was an army chaplain during the Civil War, working at churches in Kansas, Kentucky and Louisiana. After the war ended, he settled in Natchez, Mississippi, where he was an elder at the African Methodist Episcopal Church, and built a reputation as a respected community leader.

Mississippi was seeking readmission to representation in the US Congress and needed to fill two Senate seats that had been unoccupied since 1861, when it seceded from the Union. Revels was offered the shorter of two terms -- one set to expire in March 1871.

Revels took the oath of office 22 days after the ratification of the 15th Amendment, which held that Americans could not be denied the right to vote based on their race. Revels was "the 15th Amendment in flesh and blood," civil rights activist Wendell Phillips said.

Sen. Blanche K. Bruce of Mississippi was the first African American to serve a full term in the US Senate.

Born into slavery, he could not attend school, so he sneaked in some lessons from a tutor hired for his master's son. He escaped at the beginning of the Civil War and taught Black students in Missouri before moving to Mississippi, where he held several jobs, including a county sheriff and tax collector.

Like Revels, he was elected to the US senate by the Mississippi state legislature, not voters. Bruce served from 1875 to 1881.

The former slave later became a plantation owner, and lived a privileged life that was a far cry from that of his Black constituents. Despite moving in elite circles, he fought for the rights of freed slaves and was a strong advocate for Black war veterans. But Black people in Mississippi questioned his commitment to their plight.

Sen. Edward Brooke of Massachusetts was the first African American elected to the US Senate by popular vote. He's also credited with integrating the Senate barbershop with his first haircut on Capitol Hill after his win.

The former World War II Army veteran graduated from Howard University and then attended law school at Boston University. He served two full terms in the Senate, from 1967 to 1979.

Brooke did not consider himself a trailblazing politician and maintained that he represented all his constituents. "I do not intend to be a national leader of the Negro people. I intend to do my job as a senator from Massachusetts," he once declared. He died in 2015 at the age of 95.

Carol Moseley Braun shattered barriers as the first Black female US senator.

Moseley Braun was also the first woman to serve on the powerful Finance Committee after Democrat Tom Daschle gave up his seat to create a spot for her.

The Democrat from Illinois served only one term, from 1993 to 1999. Before joining the Senate, she was a prosecutor in the office of the United States Attorney in Chicago and assistant majority leader in the Illinois House of Representatives.

She defeated both the Democratic incumbent and the Republican challenger for a seat in the US Senate, becoming the first female senator from Illinois as well. But she lost her bid for reelection to the Senate and unsuccessfully ran for president in 2004.

"I cannot escape the fact that I come to the Senate as a symbol of hope and change," she said shortly after being sworn in. "Nor would I want to, because my presence in and of itself will change the US Senate."

In the nearly three decades since, there has only been one other female Black senator: Kamala Harris.