"I can and will do a better job for the people of Mississippi and the United States," Espy told supporters by email, after telegraphing the move for months.
A former U.S. Secretary of Agriculture and U.S. House member, Espy lost their 2018 special election race to fill the last two years of retired Sen. Thad Cochran's six-year term. Hyde-Smith, who was Mississippi's agriculture commissioner when Gov. Phil Bryant appointed her to temporarily take Cochran's place, became the first woman elected to Congress from Mississippi.
The campaign was rocked by a video showing Hyde-Smith praising a supporter by saying she'd attend a "public hanging" if he invited her. She called it an "exaggerated expression of regard."
The comment made Mississippi's history lynching history a central theme in the race. Espy took a shot at that history in his announcement video, saying "Cindy Hyde-Smith is hurting Mississippi - our progress and our reputation - and we simply must replace her."
If elected, Espy would be Mississippi's first African American U.S. senator since Reconstruction. The Democrat says he wants to focus on reducing poverty and increasing well-paying jobs in Mississippi, improving schools, ending Trump's trade war that's pressuring farmers financially and making health care more affordable.
Qualifying for next year's party primaries begins Jan. 2. They'll be held on March 10, the same day Mississippians vote in presidential primaries. Party runoffs, if needed, will be March 31, leaving a long stretch for nominees to face off before the November general election.
No Republicans have made any public moves to challenge Hyde-Smith in the GOP primary. During her time in office, Hyde-Smith has often been focused on rural issues and has remained loyal to President Donald Trump.
Espy's announcement comes a week after Democrat Jim Hood lost the governor's race to Republican Tate Reeves, highlighting continuing weakness for Democrats in Mississippi. More voters actually turned out for the runoff between Espy and Hyde-Smith than for the 2019 general election, and other Democrats also lost badly in statewide races.
As he did in the 2018 campaign, Espy said he'll be independent and put Mississippi's needs over loyalty to a party.
"Cindy Hyde-Smith has done little to truly help the Magnolia State," Espy said in his statement. "It feels like a new crisis dominates the headlines every day but does nothing to create jobs or improve our communities. Too often, our current senator puts party over country instead of doing what's best for our state and even our national security."
A spokesman for Hyde-Smith didn't immediately respond to a request for a comment. She's likely to have a substantial financial advantage over Espy. Federal Election Commission data shows Espy raised $100,000 through Sept. 30 and had $131,000 on hand, while Hyde-Smith raised nearly $1 million and had $583,000 on hand.
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